diff --git a/CHANGELOG b/CHANGELOG
index 5a3d3a4dc..6b4e05b92 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,12 @@
+0.9.4
+----- 
+
+ - Improved console formatting for lists and dicts
+ - Run method returns list of scripts when no argument is given
+ - Do not keep mnemonics and private keys in readline history
+ - Use KwargTuple type for call return values
+ - Bugfixes
+
 0.9.3
 -----
 
diff --git a/__main__.py b/__main__.py
index 9c65dcf1e..ea592cd12 100644
--- a/__main__.py
+++ b/__main__.py
@@ -9,7 +9,7 @@
 from lib.services import color, git
 
 
-__version__ = "0.9.3"  # did you change this in docs/conf.py as well?
+__version__ = "0.9.4"  # did you change this in docs/conf.py as well?
 if git.get_branch() != "master":
     __version__+= "-"+git.get_branch()+"-"+git.get_commit()
 
diff --git a/docs/api.rst b/docs/api.rst
index b9a15101a..36172f350 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -1096,12 +1096,16 @@ These methods are used in the console.
         Brownie environment is ready.
         >>>
 
-.. py:method:: run(script)
+.. py:method:: run(script=None)
 
     Loads a script and runs the ``main`` method within it. See :ref:`deploy` for more information.
 
+    If no argument is given, returns a list of script names from the ``scripts/`` folder.
+
     .. code-block:: python
 
+        >>> run()
+        ['token']
         >>> run('token')
 
         Transaction sent: 0xe4bd74210e56d4da8d53774dc333a1122c26a72a86fbba82220fcf5d2648d634
diff --git a/docs/conf.py b/docs/conf.py
index 7a7d2a719..5216401d3 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -26,7 +26,7 @@
 # The short X.Y version
 version = ''
 # The full version, including alpha/beta/rc tags
-release = '0.9.3'
+release = '0.9.4'
 
 
 # -- General configuration ---------------------------------------------------
diff --git a/lib/components/account.py b/lib/components/account.py
index 49fca39dd..dba980f21 100644
--- a/lib/components/account.py
+++ b/lib/components/account.py
@@ -2,7 +2,6 @@
 
 import eth_keys
 from hexbytes import HexBytes
-import json
 import os
 
 from lib.components.transaction import TransactionReceipt, raise_or_return_tx
@@ -18,6 +17,9 @@ class Accounts:
 
     def __init__(self, accounts):
         self._accounts = [Account(i) for i in accounts]
+        # prevent mnemonics and private keys from being stored in read history
+        self.add.__dict__['_private'] = True
+        self.mnemonic.__dict__['_private'] = True
 
     def __contains__(self, address):
         try:
@@ -26,9 +28,9 @@ def __contains__(self, address):
         except ValueError:
             return False
 
-    def __repr__(self):
+    def _console_repr(self):
         return str(self._accounts)
-    
+
     def __iter__(self):
         return iter(self._accounts)
 
@@ -40,14 +42,14 @@ def __delitem__(self, key):
 
     def __len__(self):
         return len(self._accounts)
-    
+
     def _check_nonce(self):
         for i in self._accounts:
             i.nonce = web3.eth.getTransactionCount(str(i))
 
-    def add(self, priv_key = None):
+    def add(self, priv_key=None):
         '''Creates a new ``LocalAccount`` instance and appends it to the container.
-        
+
         Args:
             priv_key: Private key of the account. If none is given, one is
                       randomly generated.
@@ -56,7 +58,7 @@ def add(self, priv_key = None):
             Account instance.
         '''
         if not priv_key:
-            priv_key=web3.sha3(os.urandom(8192)).hex()
+            priv_key = web3.sha3(os.urandom(8192)).hex()
         w3account = web3.eth.account.privateKeyToAccount(priv_key)
         if w3account.address in self._accounts:
             return self.at(w3account.address)
@@ -112,7 +114,7 @@ def clear(self):
 class _AccountBase:
 
     '''Base class for Account and LocalAccount'''
-    
+
     def __init__(self, addr):
         self.address = addr
         self.nonce = web3.eth.getTransactionCount(self.address)
@@ -120,6 +122,9 @@ def __init__(self, addr):
     def __hash__(self):
         return hash(self.address)
 
+    def __repr__(self):
+        return "'{0[string]}{1}{0}'".format(color, self.address)
+
     def __str__(self):
         return self.address
 
@@ -148,7 +153,7 @@ def deploy(self, contract, *args):
             * Contract instance if the transaction confirms
             * TransactionReceipt if the transaction is pending or reverts'''
         return contract.deploy(self, *args)
-    
+
     def estimate_gas(self, to, amount, data=""):
         '''Estimates the gas cost for a transaction. Raises VirtualMachineError
         if the transaction would revert.
@@ -161,10 +166,10 @@ def estimate_gas(self, to, amount, data=""):
         Returns:
             Estimated gas value in wei.'''
         return web3.eth.estimateGas({
-            'from':self.address,
-            'to':str(to),
-            'data':data,
-            'value':wei(amount)
+            'from': self.address,
+            'to': str(to),
+            'data': data,
+            'value': wei(amount)
         })
 
     def _gas_limit(self, to, amount, data=""):
@@ -179,17 +184,17 @@ def _gas_price(self):
 class Account(_AccountBase):
 
     '''Class for interacting with an Ethereum account.
-    
+
     Attributes:
         address: Public address of the account.
         nonce: Current nonce of the account.'''
-    
-    def __repr__(self):
+
+    def _console_repr(self):
         return "<Account object '{0[string]}{1}{0}'>".format(color, self.address)
-    
+
     def transfer(self, to, amount, gas_limit=None, gas_price=None):
         '''Transfers ether from this account.
-        
+
         Args:
             to: Account instance or address string to transfer to.
             amount: Amount of ether to send, in wei.
@@ -228,7 +233,7 @@ def _contract_tx(self, fn, args, tx, name, callback=None):
 class LocalAccount(_AccountBase):
 
     '''Class for interacting with an Ethereum account.
-    
+
     Attributes:
         address: Public address of the account.
         nonce: Current nonce of the account.
@@ -241,12 +246,12 @@ def __init__(self, address, account, priv_key):
         self.public_key = eth_keys.keys.PrivateKey(HexBytes(priv_key)).public_key
         super().__init__(address)
 
-    def __repr__(self):
+    def _console_repr(self):
         return "<LocalAccount object '{0[string]}{1}{0}'>".format(color, self.address)
 
     def transfer(self, to, amount, gas_limit=None, gas_price=None):
         '''Transfers ether from this account.
-        
+
         Args:
             to: Account instance or address string to transfer to.
             amount: Amount of ether to send, in wei.
@@ -274,8 +279,8 @@ def transfer(self, to, amount, gas_limit=None, gas_price=None):
     def _contract_tx(self, fn, args, tx, name, callback=None):
         try:
             tx.update({
-                'from':self.address,
-                'nonce':self.nonce,
+                'from': self.address,
+                'nonce': self.nonce,
                 'gasPrice': self._gas_price(),
                 'gas': (
                     CONFIG['active_network']['gas_limit'] or
diff --git a/lib/components/check.py b/lib/components/check.py
index b7e14f949..930f5a600 100644
--- a/lib/components/check.py
+++ b/lib/components/check.py
@@ -8,7 +8,7 @@
 
 def true(statement, fail_msg="Expected statement to be true"):
     '''Expects an object or statement to evaluate True.
-    
+
     Args:
         statement: The object or statement to check.
         fail_msg: Message to show if the check fails.'''
@@ -18,7 +18,7 @@ def true(statement, fail_msg="Expected statement to be true"):
 
 def false(statement, fail_msg="Expected statement to be False"):
     '''Expects an object or statement to evaluate False.
-    
+
     Args:
         statement: The object or statement to check.
         fail_msg: Message to show if the check fails.'''
@@ -28,14 +28,14 @@ def false(statement, fail_msg="Expected statement to be False"):
 
 def reverts(fn, args, revert_msg=None):
     '''Expects a transaction to revert.
-    
+
     Args:
         fn: ContractTx instance to call.
         args: List or tuple of contract input args.
         fail_msg: Message to show if the check fails.
         revert_msg: If set, the check only passes if the returned
                     revert message matches the given one.'''
-    try: 
+    try:
         fn(*args)
     except _VMError as e:
         if not revert_msg or revert_msg == e.revert_msg:
@@ -49,12 +49,12 @@ def reverts(fn, args, revert_msg=None):
 
 def confirms(fn, args, fail_msg="Expected transaction to confirm"):
     '''Expects a transaction to confirm.
-    
+
     Args:
         fn: ContractTx instance to call.
         args: List or tuple of contract input args.
         fail_msg: Message to show if the check fails.
-        
+
     Returns:
         TransactionReceipt instance.'''
     try:
@@ -66,7 +66,7 @@ def confirms(fn, args, fail_msg="Expected transaction to confirm"):
 
 def event_fired(tx, name, count=None, values=None):
     '''Expects a transaction to contain an event.
-    
+
     Args:
         tx: A TransactionReceipt.
         name: Name of the event expected to fire.
@@ -75,7 +75,7 @@ def event_fired(tx, name, count=None, values=None):
         values: A dict or list of dicts of {key:value} that must match
                 against the fired events. The length of values must also
                 match the number of events that fire.'''
-    events = [i for i in tx.events if i['name']==name]
+    events = [i for i in tx.events if i['name'] == name]
     if count is not None and count != len(events):
         raise AssertionError(
             "Event {} - expected {} events to fire, got {}".format(
@@ -94,12 +94,12 @@ def event_fired(tx, name, count=None, values=None):
             )
         )
     for i in range(len(values)):
-        data = dict((x['name'],x['value']) for x in events[i]['data'])
-        for k,v in values[i].items():
+        data = dict((x['name'], x['value']) for x in events[i]['data'])
+        for k, v in values[i].items():
             if k not in data:
                 print(data)
                 raise KeyError(
-                    "Event {} - does not contain value '{}'".format(name,k)
+                    "Event {} - does not contain value '{}'".format(name, k)
                 )
             if data[k] != v:
                 raise AssertionError(
@@ -111,12 +111,12 @@ def event_fired(tx, name, count=None, values=None):
 
 def event_not_fired(tx, name, fail_msg="Expected event not to fire"):
     '''Expects a transaction not to contain an event.
-    
+
     Args:
         tx: A TransactionReceipt.
         name: Name of the event expected to fire.
         fail_msg: Message to show if check fails.'''
-    if [i for i in tx.events if i['name']==name]:
+    if [i for i in tx.events if i['name'] == name]:
         raise AssertionError(fail_msg)
 
 
@@ -129,7 +129,7 @@ def equal(a, b, fail_msg="Expected values to be equal"):
         fail_msg: Message to show if check fails.'''
     a, b = _convert(a, b)
     if a != b:
-        raise AssertionError(fail_msg+": {} != {}".format(a,b))
+        raise AssertionError(fail_msg+": {} != {}".format(a, b))
 
 
 def not_equal(a, b, fail_msg="Expected values to be not equal"):
@@ -141,15 +141,19 @@ def not_equal(a, b, fail_msg="Expected values to be not equal"):
         fail_msg: Message to show if check fails.'''
     a, b = _convert(a, b)
     if a == b:
-        raise AssertionError(fail_msg+": {} == {}".format(a,b))
+        raise AssertionError(fail_msg+": {} == {}".format(a, b))
 
 
 # attempt conversion with wei before comparing equality
 def _convert(a, b):
     if a not in (None, False, True):
-        try: a = wei(a)
-        except ValueError: pass
+        try:
+            a = wei(a)
+        except (ValueError, TypeError):
+            pass
     if b not in (None, False, True):
-        try: b = wei(b)
-        except ValueError: pass
-    return a, b
\ No newline at end of file
+        try:
+            b = wei(b)
+        except (ValueError, TypeError):
+            pass
+    return a, b
diff --git a/lib/components/contract.py b/lib/components/contract.py
index 097355567..f0469c11e 100644
--- a/lib/components/contract.py
+++ b/lib/components/contract.py
@@ -4,6 +4,7 @@
 import eth_event
 import re
 
+from lib.services.datatypes import KwargTuple, format_output
 from lib.components.transaction import TransactionReceipt, VirtualMachineError
 from lib.components.eth import web3, wei
 
@@ -14,6 +15,7 @@
 
 deployed_contracts = {}
 
+
 def find_contract(address):
     address = web3.toChecksumAddress(address)
     contracts = [x for v in deployed_contracts.values() for x in v.values()]
@@ -26,43 +28,43 @@ def __init__(self, build):
         self._build = build
         self.abi = build['abi']
         self._name = build['contractName']
-        names = [i['name'] for i in self.abi if i['type']=="function"]
-        duplicates = set(i for i in names if names.count(i)>1)
+        names = [i['name'] for i in self.abi if i['type'] == "function"]
+        duplicates = set(i for i in names if names.count(i) > 1)
         if duplicates:
             raise AttributeError("Ambiguous contract functions in {}: {}".format(
                 self._name, ",".join(duplicates)))
         self.topics = eth_event.get_topics(self.abi)
         self.signatures = dict((
             i['name'],
-            web3.sha3(text="{}({})".format(i['name'],
-                ",".join(x['type'] for x in i['inputs'])
-                )).hex()[:10]
-        ) for i in self.abi if i['type']=="function")
+            web3.sha3(text="{}({})".format(
+                i['name'], ",".join(x['type'] for x in i['inputs'])
+            )).hex()[:10]
+        ) for i in self.abi if i['type'] == "function")
 
 
 class ContractContainer(_ContractBase):
 
     '''List-like container class that holds all Contract instances of the same
     type, and is used to deploy new instances of that contract.
-    
+
     Attributes:
         abi: Complete contract ABI.
         bytecode: Bytecode used to deploy the contract.
         signatures: Dictionary of {'function name': "bytes4 signature"}
         topics: Dictionary of {'event name': "bytes32 topic"}'''
-    
+
     def __init__(self, build, network):
         self.tx = None
         self.bytecode = build['bytecode']
         self._network = network
         if type(build['pcMap']) is list:
-            build['pcMap'] = dict((i.pop('pc'),i) for i in build['pcMap'])
+            build['pcMap'] = dict((i.pop('pc'), i) for i in build['pcMap'])
         super().__init__(build)
         self.deploy = ContractConstructor(self, self._name)
         deployed_contracts[self._name] = OrderedDict()
         for k, data in sorted([
-            (k,v) for k,v in build['networks'].items() if 
-            v['network']==CONFIG['active_network']['name']
+            (k, v) for k, v in build['networks'].items() if
+            v['network'] == CONFIG['active_network']['name']
         ], key=lambda k: int(k[0])):
             if web3.eth.getCode(data['address']).hex() == "0x00":
                 print("WARNING: No contract deployed at {}.".format(data['address']))
@@ -85,23 +87,23 @@ def __getitem__(self, i):
 
     def __delitem__(self, key):
         del deployed_contracts[self._name][self[key].address]
-    
+
     def __len__(self):
         return len(deployed_contracts[self._name])
 
-    def __repr__(self):
+    def _console_repr(self):
         return str(list(deployed_contracts[self._name].values()))
 
     def remove(self, contract):
         '''Removes a contract from the container.
-        
+
         Args:
             contract: Contract instance of address string of the contract.'''
         del deployed_contracts[self._name][str(contract)]
 
-    def at(self, address, owner = None, tx = None):
+    def at(self, address, owner=None, tx=None):
         '''Returns a contract address.
-        
+
         Raises ValueError if no bytecode exists at the address.
 
         Args:
@@ -126,14 +128,14 @@ def at(self, address, owner = None, tx = None):
 
 
 class ContractConstructor:
-    
+
     def __init__(self, parent, name):
         self._parent = parent
         try:
-            self.abi = [next(i for i in parent.abi if i['type']=="constructor")]
+            self.abi = [next(i for i in parent.abi if i['type'] == "constructor")]
         except:
             self.abi = []
-        
+
         self._name = name
 
     def __repr__(self):
@@ -174,7 +176,7 @@ def __call__(self, account, *args):
                     marker,
                     self._parent._network[contract][-1].address[-40:]
                 )
-        contract = web3.eth.contract(abi = self.abi, bytecode = bytecode)
+        contract = web3.eth.contract(abi=self.abi, bytecode=bytecode)
         args, tx = _get_tx(account, args)
         tx = account._contract_tx(
             contract.constructor,
@@ -201,7 +203,7 @@ def _callback(self, tx):
 class Contract(_ContractBase):
 
     '''Methods for interacting with a deployed contract.
-    
+
     Each public contract method is available as a ContractCall or ContractTx
     instance, created when this class is instantiated.
 
@@ -214,15 +216,15 @@ def __init__(self, address, build, owner, tx=None):
         self.tx = tx
         self.bytecode = web3.eth.getCode(address).hex()[2:]
         self._owner = owner
-        self._contract = web3.eth.contract(address = address, abi = self.abi)
-        for i in [i for i in self.abi if i['type']=="function"]:
+        self._contract = web3.eth.contract(address=address, abi=self.abi)
+        for i in [i for i in self.abi if i['type'] == "function"]:
             if hasattr(self, i['name']):
                 raise AttributeError(
                     "Namespace collision: '{}.{}'".format(self._name, i['name'])
                 )
-            fn = getattr(self._contract.functions,i['name'])
+            fn = getattr(self._contract.functions, i['name'])
             name = "{}.{}".format(self._name, i['name'])
-            if i['stateMutability'] in ('view','pure'):
+            if i['stateMutability'] in ('view', 'pure'):
                 setattr(self, i['name'], ContractCall(fn, i, name, owner))
             else:
                 setattr(self, i['name'], ContractTx(fn, i, name, owner))
@@ -274,7 +276,7 @@ def _format_inputs(self, args):
 
     def call(self, *args):
         '''Calls the contract method without broadcasting a transaction.
-        
+
         Args:
             *args: Contract method inputs. You can optionally provide a
                    dictionary of transaction properties as the last arg.
@@ -286,17 +288,18 @@ def call(self, *args):
             tx['from'] = str(tx['from'])
         else:
             del tx['from']
-        try: 
+        try:
             result = self._fn(*self._format_inputs(args)).call(tx)
         except ValueError as e:
             raise VirtualMachineError(e)
-        if type(result) is not list:
-            return web3.toHex(result) if type(result) is bytes else result
-        return [(web3.toHex(i) if type(i) is bytes else i) for i in result]
+
+        if type(result) is not list or len(result)==1:
+            return format_output(result)
+        return KwargTuple(result, self.abi)
 
     def transact(self, *args):
         '''Broadcasts a transaction that calls this contract method.
-        
+
         Args:
             *args: Contract method inputs. You can optionally provide a
                    dictionary of transaction properties as the last arg.
@@ -335,7 +338,7 @@ def __init__(self, fn, abi, name, owner):
 
     def __call__(self, *args):
         '''Broadcasts a transaction that calls this contract method.
-        
+
         Args:
             *args: Contract method inputs. You can optionally provide a
                    dictionary of transaction properties as the last arg.
@@ -348,21 +351,21 @@ def __call__(self, *args):
 class ContractCall(_ContractMethod):
 
     '''A public view or pure contract method.
-    
+
     Args:
         abi: Contract ABI specific to this method.
         signature: Bytes4 method signature.'''
 
     def __call__(self, *args):
         '''Calls the contract method without broadcasting a transaction.
-        
+
         Args:
             *args: Contract method inputs. You can optionally provide a
                    dictionary of transaction properties as the last arg.
 
         Returns:
             Contract method return value(s).'''
-        if config.ARGV['mode']=="script" and CONFIG['test']['always_transact']:
+        if config.ARGV['mode'] == "script" and CONFIG['test']['always_transact']:
             tx = self.transact(*args)
             return tx.return_value
         return self.call(*args)
@@ -374,7 +377,7 @@ def _get_tx(owner, args):
         args, tx = (args[:-1], args[-1])
         if 'from' not in tx:
             tx['from'] = owner
-        for key in [i for i in ['value','gas','gasPrice'] if i in tx]:
+        for key in [i for i in ('value', 'gas', 'gasPrice') if i in tx]:
             tx[key] = wei(tx[key])
     else:
         tx = {'from': owner}
@@ -387,19 +390,19 @@ def _format_inputs(name, inputs, types):
     if len(inputs) and not len(types):
         raise AttributeError("{} requires no arguments".format(name))
     if len(inputs) != len(types):
-        raise AttributeError(
-            "{} requires the following arguments: {}".format(
-            name,",".join(types)))
+        raise AttributeError("{} requires the following arguments: {}".format(
+            name, ",".join(types)
+        ))
     for i, type_ in enumerate(types):
-        if type_[-1]=="]":
+        if type_[-1] == "]":
             # input value is an array, have to check every item
-            t,length = type_.rstrip(']').rsplit('[', maxsplit=1)
+            t, length = type_.rstrip(']').rsplit('[', maxsplit=1)
             if length != "" and len(inputs[i]) != int(length):
                 raise ValueError(
                     "'{}': Argument {}, sequence has a ".format(name, i) +
                     "length of {}, should be {}".format(len(inputs[i]), type_)
                     )
-            inputs[i] = _format_inputs(name, inputs[i],[t]*len(inputs[i]))
+            inputs[i] = _format_inputs(name, inputs[i], [t]*len(inputs[i]))
             continue
         try:
             if "address" in type_:
@@ -407,12 +410,15 @@ def _format_inputs(name, inputs, types):
             if "int" in type_:
                 inputs[i] = wei(inputs[i])
             elif "bytes" in type_ and type(inputs[i]) is not bytes:
-                if type(inputs[i]) is not str:
-                    inputs[i]=int(inputs[i]).to_bytes(int(type_[5:]), "big")
-                elif inputs[i][:2]!="0x":
-                    inputs[i]=inputs[i].encode() 
+                if type(inputs[i]) is str:
+                    if inputs[i][:2] != "0x":
+                        inputs[i] = inputs[i].encode()
+                    elif type_ != "bytes":
+                        inputs[i] = int(inputs[i], 16).to_bytes(int(type_[5:]), "big")
+                else:
+                    inputs[i] = int(inputs[i]).to_bytes(int(type_[5:]), "big")
         except:
             raise ValueError(
                 "'{}': Argument {}, could not convert {} '{}' to type {}".format(
-                    name,i,type(inputs[i]).__name__,inputs[i],type_))
-    return inputs
\ No newline at end of file
+                    name, i, type(inputs[i]).__name__, inputs[i], type_))
+    return inputs
diff --git a/lib/components/eth.py b/lib/components/eth.py
index ae2a6547d..326450fea 100644
--- a/lib/components/eth.py
+++ b/lib/components/eth.py
@@ -19,7 +19,7 @@ def __init__(self):
 
     def _connect(self):
         web3 = Web3(HTTPProvider(CONFIG['active_network']['host']))
-        for name, fn in [(i,getattr(web3,i)) for i in dir(web3) if i[0].islower()]:
+        for name, fn in [(i, getattr(web3, i)) for i in dir(web3) if i[0].islower()]:
             setattr(self, name, fn)
         for i in range(20):
             if web3.isConnected():
@@ -29,18 +29,19 @@ def _connect(self):
             CONFIG['active_network']['host']
         ))
 
+
 class Rpc:
 
     '''Methods for interacting with ganache-cli when running a local
     RPC environment.'''
-    
+
     def __init__(self, network):
         rpc = Popen(
             CONFIG['active_network']['test-rpc'].split(' '),
-            stdout = DEVNULL,
-            stdin = DEVNULL,
-            stderr = DEVNULL,
-            start_new_session = True
+            stdout=DEVNULL,
+            stdin=DEVNULL,
+            stderr=DEVNULL,
+            start_new_session=True
         )
         self._rpc = rpc
         self._time_offset = 0
@@ -60,7 +61,7 @@ def time(self):
 
     def sleep(self, seconds):
         '''Increases the time within the test RPC.
-        
+
         Args:
             seconds (int): Number of seconds to increase the time by.'''
         if type(seconds) is not int:
@@ -69,7 +70,7 @@ def sleep(self, seconds):
             "evm_increaseTime", [seconds]
         )['result']
 
-    def mine(self, blocks = 1):
+    def mine(self, blocks=1):
         '''Increases the block height within the test RPC.
 
         Args:
@@ -77,20 +78,21 @@ def mine(self, blocks = 1):
         if type(blocks) is not int:
             raise TypeError("blocks must be an integer value")
         for i in range(blocks):
-             web3.providers[0].make_request("evm_mine",[])
+            web3.providers[0].make_request("evm_mine", [])
         return "Block height at {}".format(web3.eth.blockNumber)
 
     def snapshot(self):
         '''Takes a snapshot of the current state of the EVM.'''
-        self._snapshot_id = web3.providers[0].make_request("evm_snapshot",[])['result']
+        self._snapshot_id = web3.providers[0].make_request("evm_snapshot", [])['result']
         return "Snapshot taken at block height {}".format(web3.eth.blockNumber)
 
     def revert(self):
         '''Reverts the EVM to the most recently taken snapshot.'''
         if not self._snapshot_id:
             raise ValueError("No snapshot set")
-        web3.providers[0].make_request("evm_revert",[self._snapshot_id])
+        web3.providers[0].make_request("evm_revert", [self._snapshot_id])
         self.snapshot()
+        self.sleep(0)
         self._network._network_dict['accounts']._check_nonce()
         height = web3.eth.blockNumber
         history = self._network._network_dict['history']
@@ -113,7 +115,7 @@ def _watch_rpc(rpc):
 
 def wei(value):
     '''Converts a value to wei.
-    
+
     Useful for the following formats:
         * a string specifying the unit: "10 ether", "300 gwei", "0.25 shannon"
         * a large float in scientific notation, where direct conversion to int
@@ -141,11 +143,11 @@ def wei(value):
     try:
         return int(value)
     except ValueError:
-        raise ValueError("Unknown denomination: {}".format(value))    
+        raise ValueError("Unknown denomination: {}".format(value))
 
 
 web3 = web3()
 UNITS = {
     'kwei': 3, 'babbage': 3, 'mwei': 6, 'lovelace': 6, 'gwei': 9, 'shannon': 9,
     'microether': 12, 'szabo': 12, 'milliether': 15, 'finney': 15, 'ether': 18
-}
\ No newline at end of file
+}
diff --git a/lib/components/network.py b/lib/components/network.py
index 65e2f85f7..44e710d5b 100644
--- a/lib/components/network.py
+++ b/lib/components/network.py
@@ -161,11 +161,13 @@ def save(self):
             print("{0[error]}ERROR{0}: Unable to save environment due to unhandled {1}: {2}".format(
                 color, type(e).__name__, e))
 
-    def run(self, name):
+    def run(self, name=None):
         '''Loads a module from the scripts/ folder and runs the main() method.
 
         Args:
             name (string): name of the script.'''
+        if not name:
+            return([i[:-3] for i in os.listdir('scripts') if i[0]!="_" and i[-3:]==".py"])
         if not os.path.exists("scripts/{}.py".format(name)):
             print("{0[error]}ERROR{0}: Cannot find scripts/{1}.py".format(color, name))
             return
diff --git a/lib/components/transaction.py b/lib/components/transaction.py
index 1d72ecd0e..9cccb1c27 100644
--- a/lib/components/transaction.py
+++ b/lib/components/transaction.py
@@ -10,6 +10,7 @@
 from lib.components import contract
 from lib.components.eth import web3
 from lib.services.compiler import compile_contracts
+from lib.services.datatypes import KwargTuple, format_output
 from lib.services import config
 from lib.services import color
 CONFIG = config.CONFIG
@@ -33,28 +34,33 @@
 class VirtualMachineError(Exception):
 
     '''Raised when a call to a contract causes an EVM exception.
-    
+
     Attributes:
         revert_msg: The returned error string, if any.
         source: The contract source code where the revert occured, if available.'''
 
     revert_msg = ""
     source = ""
-    
+
     def __init__(self, exc):
         if type(exc) is not dict:
-            exc = eval(str(exc))
+            try:
+                exc = eval(str(exc))
+            except SyntaxError:
+                exc = {'message': str(exc)}
+        if len(exc['message'].split('revert ', maxsplit=1)) > 1:
+            self.revert_msg = exc['message'].split('revert ')[-1]
         if 'source' in exc:
             self.source = exc['source']
-        if len(exc['message'].split('revert ', maxsplit=1))>1:
-            self.revert_msg = exc['message'].split('revert ')[-1]
-        super().__init__(exc['message'])
+            super().__init__(exc['message']+"\n"+exc['source'])
+        else:
+            super().__init__(exc['message'])
 
 
 def raise_or_return_tx(exc):
     data = eval(str(exc))
     try:
-        return next(i for i in data['data'].keys() if i[:2]=="0x")
+        return next(i for i in data['data'].keys() if i[:2] == "0x")
     except Exception:
         raise VirtualMachineError(exc)
 
@@ -67,7 +73,7 @@ class TransactionReceipt:
     * Before the tx confirms, many values are set to None.
     * trace, revert_msg return_value, and events from a reverted tx
       are only available if debug_traceTransaction is enabled in the RPC.
-    
+
     Attributes:
         fn_name: Name of the method called in the transaction
         txid: Transaction ID
@@ -121,9 +127,10 @@ def __init__(self, txid, sender=None, silent=False, name='', callback=None):
         try:
             t.join()
             if config.ARGV['mode'] == "script" and not self.status:
-                raise VirtualMachineError(
-                    {"message": "revert "+(self.revert_msg or ""), "source":self.error(1)}
-                )
+                raise VirtualMachineError({
+                    "message": "revert "+(self.revert_msg or ""),
+                    "source": self.error(1)
+                })
         except KeyboardInterrupt:
             if config.ARGV['mode'] == "script":
                 raise
@@ -131,7 +138,8 @@ def __init__(self, txid, sender=None, silent=False, name='', callback=None):
     def _await_confirm(self, silent, callback):
         while True:
             tx = web3.eth.getTransaction(self.txid)
-            if tx: break
+            if tx:
+                break
             time.sleep(0.5)
         if not self.sender:
             self.sender = tx['from']
@@ -190,7 +198,7 @@ def __hash__(self):
         return hash(self.txid)
 
     def __getattr__(self, attr):
-        if attr not in ('events','return_value', 'revert_msg', 'trace'):
+        if attr not in ('events', 'return_value', 'revert_msg', 'trace'):
             raise AttributeError(
                 "'TransactionReceipt' object has no attribute '{}'".format(attr)
             )
@@ -227,7 +235,7 @@ def info(self):
                 for i in event['data']:
                     color.print_colors(
                         "      {0[name]}: {0[value]}".format(i),
-                        value = None if i['decoded'] else "dull"
+                        value=None if i['decoded'] else "dull"
                     )
             print()
 
@@ -244,11 +252,11 @@ def _get_trace(self):
         self.trace = []
         self.return_value = None
         self.revert_msg = None
-        if (self.input=="0x" and self.gas_used == 21000) or self.contract_address:
+        if (self.input == "0x" and self.gas_used == 21000) or self.contract_address:
             return
         trace = web3.providers[0].make_request(
             'debug_traceTransaction',
-            [self.txid,{}]
+            [self.txid, {}]
         )
         if 'error' in trace:
             raise ValueError(trace['error']['message'])
@@ -256,7 +264,7 @@ def _get_trace(self):
         c = contract.find_contract(self.receiver or self.contract_address)
         last = {0: {
             'address': self.receiver or self.contract_address,
-            'contract':c._name,
+            'contract': c._name,
             'fn': [self.fn_name.split('.')[-1]],
         }}
         pc = c._build['pcMap'][0]
@@ -282,7 +290,7 @@ def _get_trace(self):
                 last[trace[i]['depth']] = {
                     'address': address,
                     'contract': c._name,
-                    'fn': [next(k for k,v in c.signatures.items() if v==sig)],
+                    'fn': [next(k for k, v in c.signatures.items() if v == sig)],
                     }
             trace[i].update({
                 'address': last[trace[i]['depth']]['address'],
@@ -304,9 +312,9 @@ def _get_trace(self):
                         fn = source[:source.index('(')].split('.')[-1]
                     else:
                         fn = last[trace[i]['depth']]['fn'][-1]
-                    last[trace[i]['depth']]['fn'].append(fn)   
+                    last[trace[i]['depth']]['fn'].append(fn)
             # jump 'o' is coming out of an internal function
-            elif pc['jump'] == "o" and len(last[trace[i]['depth']]['fn'])>1 :
+            elif pc['jump'] == "o" and len(last[trace[i]['depth']]['fn']) > 1:
                 last[trace[i]['depth']]['fn'].pop()
 
     def _evaluate_trace(self):
@@ -330,9 +338,13 @@ def _evaluate_trace(self):
             self.return_value = eth_abi.decode_abi(abi, data)
             if not self.return_value:
                 return
-            self.return_value = [_decode_abi(i) for i in self.return_value]
             if len(self.return_value) == 1:
-                self.return_value = self.return_value[0]
+                self.return_value = format_output(self.return_value[0])
+            else:
+                self.return_value = KwargTuple(
+                    self.return_value,
+                    getattr(c, self.fn_name.split('.')[-1]).abi
+                )
         else:
             self.events = []
             # get revert message
@@ -349,7 +361,7 @@ def _evaluate_trace(self):
                 self.events = eth_event.decode_trace(self.trace, topics())
             except:
                 pass
-            
+
     def call_trace(self):
         '''Displays the sequence of contracts and functions called while
         executing this transaction, and the structLog index where each call
@@ -358,7 +370,6 @@ def call_trace(self):
         trace = self.trace
         sep = max(i['jumpDepth'] for i in trace)
         idx = 0
-        depth = 0
         for i in range(1, len(trace)):
             if (
                 trace[i]['depth'] == trace[i-1]['depth'] and
@@ -372,23 +383,21 @@ def call_trace(self):
     def error(self, pad=3):
         '''Displays the source code that caused the transaction to revert.'''
         try:
-            trace = next(i for i in self.trace if i['op'] in ("REVERT", "INVALID")) 
+            trace = next(i for i in self.trace if i['op'] in ("REVERT", "INVALID"))
         except StopIteration:
-            return
+            return ""
         span = (trace['source']['start'], trace['source']['stop'])
         source = open(trace['source']['filename'], encoding="utf-8").read()
-        newlines = [i for i in range(len(source)) if source[i]=="\n"]
-        start = newlines.index(next(i for i in newlines if i>=span[0]))
-        stop = newlines.index(next(i for i in newlines if i>=span[1]))
+        newlines = [i for i in range(len(source)) if source[i] == "\n"]
+        start = newlines.index(next(i for i in newlines if i >= span[0]))
+        stop = newlines.index(next(i for i in newlines if i >= span[1]))
         ln = start + 1
         start = newlines[max(start-(pad+1), 0)]
         stop = newlines[min(stop+pad, len(newlines)-1)]
-        result = (
-            ('{0[dull]}File {0[string]}"{1}"{0[dull]}, ' +
-            'line {0[value]}{2}{0[dull]}, in {0[callable]}{3}').format(
-                color, trace['source']['filename'], ln, trace['fn']
-            )
-        )
+        result = ((
+            '{0[dull]}File {0[string]}"{1}"{0[dull]}, ' +
+            'line {0[value]}{2}{0[dull]}, in {0[callable]}{3}'
+        ).format(color, trace['source']['filename'], ln, trace['fn']))
         result += ("{0[dull]}{1}{0}{2}{0[dull]}{3}{0}".format(
             color,
             source[start:span[0]],
@@ -412,10 +421,10 @@ def _profile_gas(fn_name, gas_used):
     gas_profile.setdefault(
         fn_name,
         {
-            'avg':0,
-            'high':0,
-            'low':float('inf'),
-            'count':0
+            'avg': 0,
+            'high': 0,
+            'low': float('inf'),
+            'count': 0
         }
     )
     gas = gas_profile[fn_name]
@@ -428,6 +437,8 @@ def _profile_gas(fn_name, gas_used):
 
 
 _topics = {}
+
+
 def topics():
     '''Generates event topics and saves them in brownie/topics.json'''
     if _topics:
@@ -439,8 +450,9 @@ def topics():
         ))
     except (FileNotFoundError, json.decoder.JSONDecodeError):
         topics = {}
+    _topics.update(topics)
     contracts = compile_contracts()
-    events = [x for i in contracts.values() for x in i['abi'] if x['type']=="event"]
+    events = [x for i in contracts.values() for x in i['abi'] if x['type'] == "event"]
     _topics.update(eth_event.get_event_abi(events))
     json.dump(
         _topics,
@@ -449,11 +461,3 @@ def topics():
         indent=4
     )
     return _topics
-
-
-def _decode_abi(value):
-    if type(value) is tuple:
-        return [_decode_abi(i) for i in value]
-    elif type(value) is bytes:
-        return "0x"+value.hex()
-    return value
diff --git a/lib/console.py b/lib/console.py
index f593e0d0a..23de2aec8 100644
--- a/lib/console.py
+++ b/lib/console.py
@@ -8,6 +8,7 @@
 
 from lib.components.network import Network
 from lib.components.contract import _ContractBase, _ContractMethod
+from lib.services.datatypes import StrictDict, KwargTuple
 from lib.services import color, config
 CONFIG = config.CONFIG
 
@@ -38,27 +39,15 @@ def _run(self):
         try:
             readline.read_history_file("build/.history")
         except FileNotFoundError:
-            pass
+            open("build/.history", 'w').write("")
         while True:
             if not self._multiline:
                 try:
-                    cmd = input(self._prompt)
+                    cmd = self._input(self._prompt)
                 except KeyboardInterrupt:
                     sys.stdout.write("\nUse exit() or Ctrl-D (i.e. EOF) to exit.\n")
                     sys.stdout.flush()
                     continue
-                except EOFError:
-                    print()
-                    cmd = "exit()"
-                if cmd == "exit()":
-                    try:
-                        readline.remove_history_item(
-                            readline.get_current_history_length() - 1
-                        )
-                    except ValueError:
-                        pass
-                    readline.write_history_file("build/.history")
-                    return
                 if not cmd.strip():
                     continue
                 if cmd.rstrip()[-1] == ":":
@@ -66,14 +55,14 @@ def _run(self):
                     self._prompt = "... "
                     continue
             else:
-                try: 
-                    new_cmd = input('... ')
+                try:
+                    new_cmd = self._input("... ")
                 except KeyboardInterrupt:
                     print()
                     self._multiline = False
                     self._prompt = ">>> "
                     continue
-                if new_cmd: 
+                if new_cmd:
                     cmd += '\n' + new_cmd
                     continue
             if [i for i in ['{}', '[]', '()'] if cmd.count(i[0]) > cmd.count(i[1])]:
@@ -82,23 +71,30 @@ def _run(self):
             self._multiline = False
             self._prompt = ""
             try:
-                try: 
+                try:
                     local_['_result'] = None
                     exec('_result = ' + cmd, self.__dict__, local_)
                     r = local_['_result']
-                    if r != None:
-                        if type(r) in (dict, config.StrictDict) and r:
+                    if r is not None:
+                        if type(r) in (dict, StrictDict) and r:
                             color.pretty_dict(r)
+                        elif type(r) in (list, tuple, KwargTuple):
+                            color.pretty_list(r)
                         elif type(r) is str:
                             print(r)
+                        elif hasattr(r, '_console_repr'):
+                            print(r._console_repr())
                         else:
                             print(repr(r))
                 except SyntaxError:
                     exec(cmd, self.__dict__, local_)
+                except SystemExit:
+                    return
             except:
                 print(color.format_tb(sys.exc_info(), start=1))
             self._prompt = ">>> "
 
+    # replaces builtin print method, for threadsafe printing
     def _print(self, *args, sep=' ', end='\n', file=sys.stdout, flush=False):
         with self._print_lock:
             ln = readline.get_line_buffer()
@@ -107,14 +103,33 @@ def _print(self, *args, sep=' ', end='\n', file=sys.stdout, flush=False):
             file.write(self._prompt+ln)
             file.flush()
 
+    # replaces builtin dir method, for pretty and easier to read output
     def _dir(self, obj=None):
         if obj is None:
             obj = self
-        results = [(i,getattr(obj,i)) for i in builtins.dir(obj) if i[0]!="_"]
+        results = [(i, getattr(obj, i)) for i in builtins.dir(obj) if i[0] != "_"]
         print("["+"{}, ".format(color()).join(
             _dir_color(i[1])+i[0] for i in results
         )+color()+"]")
 
+    # save user input to readline history file, filter for private keys
+    def _input(self, prompt):
+        response = input(prompt)
+        try:
+            cls_, method = response[:response.index("(")].split(".")
+            cls_ = getattr(self, cls_)
+            method = getattr(cls_, method)
+            if hasattr(method, "_private"):
+                readline.replace_history_item(
+                    readline.get_current_history_length() - 1,
+                    response[:response.index("(")] + "()"
+                )
+        except (ValueError, AttributeError):
+            pass
+        readline.append_history_file(1, "build/.history")
+        return response
+
+
 def _dir_color(obj):
     if type(obj).__name__ == "module":
         return color('module')
@@ -129,13 +144,17 @@ def _dir_color(obj):
         return color('value')
     return color('callable')
 
+
 def main():
-    args = docopt(__doc__)
+    docopt(__doc__)
 
     console = Console()
-
     network = Network(console)
     print("Brownie environment is ready.")
 
-    console._run()
-    network.save()
\ No newline at end of file
+    try:
+        console._run()
+    except EOFError:
+        sys.stdout.write('\n')
+    finally:
+        network.save()
diff --git a/lib/services/color.py b/lib/services/color.py
index 04a0d4cff..fde5041a4 100755
--- a/lib/services/color.py
+++ b/lib/services/color.py
@@ -3,6 +3,7 @@
 import sys
 import traceback
 
+from lib.services.datatypes import StrictDict
 from lib.services import config
 CONFIG = config.CONFIG
 
@@ -38,9 +39,12 @@ def __call__(self, color = None):
         if not color:
             return BASE+"m"
         color = color.split()
-        if len(color) == 2:
-            return BASE+MODIFIERS[color[0]]+COLORS[color[1]]+"m"
-        return BASE+COLORS[color[0]]+"m"
+        try:
+            if len(color) == 2:
+                return BASE+MODIFIERS[color[0]]+COLORS[color[1]]+"m"
+            return BASE+COLORS[color[0]]+"m"
+        except KeyError:
+            return BASE+"m"
 
     def __str__(self):
         return BASE+"m"
@@ -48,33 +52,77 @@ def __str__(self):
     def __getitem__(self, color):
         return self(color)
 
+    # format dicts for console printing
     def pretty_dict(self, value, indent = 0, start=True):
         if start:
             sys.stdout.write(' '*indent+'{}{{'.format(self['dull']))
         indent+=4
-        for c,k in enumerate(sorted(value)):
+        for c,k in enumerate(sorted(value, key= lambda k: str(k))):
             if c:
                 sys.stdout.write(',')
             sys.stdout.write('\n'+' '*indent)
-            
             if type(k) is str:
                 sys.stdout.write("'{0[key]}{1}{0[dull]}': ".format(self, k))
             else:
                 sys.stdout.write("{0[key]}{1}{0[dull]}: ".format(self, k))
-            if type(value[k]) in (dict, config.StrictDict):
+            if type(value[k]) in (dict, StrictDict):
                 sys.stdout.write('{')
-                self.json(value[k], indent,False)
+                self.pretty_dict(value[k], indent,False)
                 continue
-            if type(value[k]) is str:
-                sys.stdout.write('"{0[string]}{1}{0[dull]}"'.format(self, value[k]))
-            else:
-                sys.stdout.write('{0[value]}{1}{0[dull]}'.format(self, value[k]))
+            if type(value[k]) in (list, tuple):
+                sys.stdout.write(str(value[k])[0])
+                self.pretty_list(value[k], indent, False)
+                continue
+            self._write(value[k])
         indent-=4
         sys.stdout.write('\n'+' '*indent+'}')
         if start:
             sys.stdout.write('\n{}'.format(self))
         sys.stdout.flush()
 
+    # format lists for console printing
+    def pretty_list(self, value, indent = 0, start=True):
+        brackets = str(value)[0],str(value)[-1]
+        if start:
+            sys.stdout.write(' '*indent+'{}{}'.format(self['dull'],brackets[0]))
+        if value and len(value)==len([i for i in value if type(i) is dict]):
+            # list of dicts
+            sys.stdout.write('\n'+' '*(indent+4)+'{')
+            for c,i in enumerate(value):
+                if c:
+                    sys.stdout.write(',')
+                self.pretty_dict(i, indent+4, False)
+            sys.stdout.write('\n'+  ' '*indent+brackets[1])
+        elif (
+            value and len(value)==len([i for i in value if type(i) is str]) and
+            set(len(i) for i in value) == {64}
+        ):
+            # list of bytes32 hexstrings (stack trace)
+            for c,i in enumerate(value):
+                if c:
+                    sys.stdout.write(',')
+                sys.stdout.write('\n'+' '*(indent+4))
+                self._write(i)
+            sys.stdout.write('\n'+' '*indent+brackets[1])
+        else:
+            # all other cases
+            for c, i in enumerate(value):
+                if c:
+                    sys.stdout.write(', ')
+                self._write(i)
+            sys.stdout.write(brackets[1])
+        if start:
+            sys.stdout.write('\n{}'.format(self))
+        sys.stdout.flush()
+
+    def _write(self, value):
+        if type(value) is str:
+            sys.stdout.write('"{0[string]}{1}{0[dull]}"'.format(self, value))
+        else:
+            sys.stdout.write('{0[value]}{1}{0[dull]}'.format(self, value))
+
+
+    # format transaction related console outputs
     def print_colors(self, msg, key = None, value=None):
         if key is None:
             key = 'key'
diff --git a/lib/services/config.py b/lib/services/config.py
index 38d65cbdd..266a02fe7 100644
--- a/lib/services/config.py
+++ b/lib/services/config.py
@@ -4,43 +4,14 @@
 import os
 import sys
 
-
-# dict subclass that prevents adding new keys when locked
-class StrictDict(dict):
-
-    def __init__(self, values={}):
-        self._locked = False
-        super().__init__()
-        self.update(values)
-
-    def __setitem__(self, key, value):
-        if self._locked and key not in self:
-            raise KeyError("{} is not a known config setting".format(key))
-        if type(value) is dict:
-            value = StrictDict(value)
-        super().__setitem__(key, value)
-
-    def update(self,arg):
-        for k,v in arg.items():
-            self.__setitem__(k,v)
-
-    def _lock(self):
-        for v in [i for i in self.values() if type(i) is StrictDict]:
-            v._lock()
-        self._locked = True
-
-    def _unlock(self):
-        for v in [i for i in self.values() if type(i) is StrictDict]:
-            v._unlock()
-        self._locked = False
-
+from lib.services.datatypes import StrictDict, FalseyDict
 
 # must happen in this order, color imports CONFIG
 CONFIG = StrictDict()
 from lib.services import color
 
 
-def load_config(network = None):
+def load_config(network=None):
     # set folders
     folder = sys.modules['__main__'].__file__
     folder = folder[:folder.rfind("/")]
@@ -53,7 +24,7 @@ def load_config(network = None):
         'project': os.path.abspath('.')
     }
     folders = os.path.abspath('.').split('/')
-    for i in range(len(folders),0,-1):
+    for i in range(len(folders), 0, -1):
         folder = '/'.join(folders[:i])
         if os.path.exists(folder+'/brownie-config.json'):
             CONFIG['folders']['project'] = folder
@@ -66,12 +37,12 @@ def load_config(network = None):
         _recursive_update(CONFIG, local_conf)
     try:
         CONFIG['logging'] = CONFIG['logging'][sys.argv[1]]
-        CONFIG['logging'].setdefault('tx',0)
-        CONFIG['logging'].setdefault('exc',0)
-        for k,v in [(k,v) for k,v in CONFIG['logging'].items() if type(v) is list]:
+        CONFIG['logging'].setdefault('tx', 0)
+        CONFIG['logging'].setdefault('exc', 0)
+        for k, v in [(k, v) for k, v in CONFIG['logging'].items() if type(v) is list]:
             CONFIG['logging'][k] = v[1 if '--verbose' in sys.argv else 0]
     except:
-        CONFIG['logging'] = {"tx":1 ,"exc":1}
+        CONFIG['logging'] = {"tx": 1, "exc": 1}
 
     # modify network settings
     if not network:
@@ -79,7 +50,7 @@ def load_config(network = None):
     try:
         CONFIG['active_network'] = CONFIG['networks'][network]
         CONFIG['active_network']['name'] = network
-        for key,value in CONFIG['network_defaults'].items():
+        for key, value in CONFIG['network_defaults'].items():
             if key not in CONFIG['active_network']:
                 CONFIG['active_network'][key] = value
         if 'persist' not in CONFIG['active_network']:
@@ -94,32 +65,18 @@ def load_config(network = None):
     CONFIG._lock()
 
 
-# merges project .json with brownie .json 
+# merges project .json with brownie .json
 def _recursive_update(original, new):
     for k in new:
         if type(new[k]) is dict and k in original:
             _recursive_update(original[k], new[k])
-        else: original[k] = new[k]
-
-
-# dict container that returns False if key is not present
-class FalseyDict:
-
-    def __init__(self):
-        self._dict = {}
-
-    def __setitem__(self, key, value):
-        self._dict[key] = value
-
-    def __getitem__(self, key):
-        if key in self._dict:
-            return self._dict[key]
-        return False
+        else:
+            original[k] = new[k]
 
 
 # move argv flags into FalseyDict
 ARGV = FalseyDict()
-for key in [i for i in sys.argv if i[:2]=="--"]:
+for key in [i for i in sys.argv if i[:2] == "--"]:
     idx = sys.argv.index(key)
     if len(sys.argv) >= idx+2 and sys.argv[idx+1][:2] != "--":
         ARGV[key[2:]] = sys.argv[idx+1]
@@ -127,8 +84,8 @@ def __getitem__(self, key):
         ARGV[key[2:]] = True
 
 # used to determine various behaviours in other modules
-if len(sys.argv)>1:
+if len(sys.argv) > 1:
     ARGV['mode'] = "console" if sys.argv[1] == "console" else "script"
 
 # load config
-load_config(ARGV['network'])
\ No newline at end of file
+load_config(ARGV['network'])
diff --git a/lib/services/datatypes.py b/lib/services/datatypes.py
new file mode 100644
index 000000000..cf292bb3b
--- /dev/null
+++ b/lib/services/datatypes.py
@@ -0,0 +1,98 @@
+#!/usr/bin/python3
+
+
+# dict subclass that prevents adding new keys when locked
+class StrictDict(dict):
+
+    def __init__(self, values={}):
+        self._locked = False
+        super().__init__()
+        self.update(values)
+
+    def __setitem__(self, key, value):
+        if self._locked and key not in self:
+            raise KeyError("{} is not a known config setting".format(key))
+        if type(value) is dict:
+            value = StrictDict(value)
+        super().__setitem__(key, value)
+
+    def update(self, arg):
+        for k, v in arg.items():
+            self.__setitem__(k, v)
+
+    def _lock(self):
+        for v in [i for i in self.values() if type(i) is StrictDict]:
+            v._lock()
+        self._locked = True
+
+    def _unlock(self):
+        for v in [i for i in self.values() if type(i) is StrictDict]:
+            v._unlock()
+        self._locked = False
+
+
+# tuple/dict hybrid used for return values
+class KwargTuple:
+
+    def __init__(self, values, abi):
+        values = format_output(values)
+        self._tuple = tuple(values)
+        self._abi = abi
+        self._dict = {}
+        for c, i in enumerate(abi['outputs']):
+            if not i['name']:
+                continue
+            self._dict[i['name']] = values[c]
+        for i in ('count', 'index'):
+            setattr(self, i, getattr(self._tuple, i))
+        for i in ('items', 'keys', 'values'):
+            setattr(self, i, getattr(self._dict, i))
+
+    def _console_repr(self):
+        return repr(self._tuple)
+
+    def __str__(self):
+        return str(self._tuple)
+
+    def __eq__(self, other):
+        return self._tuple == other
+
+    def __getitem__(self, key):
+        if type(key) in (int, slice):
+            return self._tuple[key]
+        return self._dict[key]
+
+    def __contains__(self, value):
+        return value in self._tuple
+
+    def __iter__(self):
+        return iter(self._tuple)
+
+    def __len__(self):
+        return len(self._tuple)
+
+    def copy(self):
+        return KwargTuple(self._tuple, self._abi)
+
+
+# dict container that returns False if key is not present
+class FalseyDict:
+
+    def __init__(self):
+        self._dict = {}
+
+    def __setitem__(self, key, value):
+        self._dict[key] = value
+
+    def __getitem__(self, key):
+        if key in self._dict:
+            return self._dict[key]
+        return False
+
+
+def format_output(value):
+    if type(value) in (tuple, list):
+        return tuple(format_output(i) for i in value)
+    elif type(value) is bytes:
+        return "0x"+value.hex()
+    return value