diff --git a/mmpy_bot/function.py b/mmpy_bot/function.py
index 1149d526..737754ef 100644
--- a/mmpy_bot/function.py
+++ b/mmpy_bot/function.py
@@ -6,6 +6,7 @@
 import re
 import shlex
 from abc import ABC, abstractmethod
+from itertools import islice
 from typing import TYPE_CHECKING, Callable, Optional, Sequence, Union
 
 import click
@@ -85,15 +86,11 @@ def __init__(
         self.needs_mention = needs_mention
         self.silence_fail_msg = silence_fail_msg
 
-        if allowed_users is None:
-            self.allowed_users = []
-        else:
-            self.allowed_users = [user.lower() for user in allowed_users]
+        self.allowed_users = [user.lower() for user in (allowed_users or [])]
 
-        if allowed_channels is None:
-            self.allowed_channels = []
-        else:
-            self.allowed_channels = [channel.lower() for channel in allowed_channels]
+        self.allowed_channels = [
+            channel.lower() for channel in (allowed_channels or [])
+        ]
 
         # Default for non-click functions
         _function: Union[Callable, click.Command] = self.function
@@ -115,8 +112,8 @@ def __init__(
         if _function is not None:
             self.name = _function.__qualname__
 
-        argspec = list(inspect.signature(_function).parameters.keys())
-        if not argspec[:2] == ["self", "message"]:
+        argspec = list(inspect.signature(_function).parameters)[:2]
+        if argspec != ["self", "message"]:
             raise TypeError(
                 "Any message listener function should at least have the positional"
                 f" arguments `self` and `message`, but function {self.name} has"
@@ -187,11 +184,9 @@ def listen_to(
     """Wrap the given function in a MessageFunction class so we can register some
     properties."""
 
-    if allowed_users is None:
-        allowed_users = []
+    allowed_users = allowed_users or []
 
-    if allowed_channels is None:
-        allowed_channels = []
+    allowed_channels = allowed_users or []
 
     def wrapped_func(func):
         reg = regexp
diff --git a/tests/integration_tests/utils.py b/tests/integration_tests/utils.py
index 589bce96..fe8a589c 100644
--- a/tests/integration_tests/utils.py
+++ b/tests/integration_tests/utils.py
@@ -34,7 +34,7 @@ def expect_reply(driver: Driver, post: Dict, wait=RESPONSE_TIMEOUT, retries=1):
             reply = thread_info["posts"][reply_id]
             break
 
-    if not reply:
+    if reply is None:
         raise ValueError("Expected a response, but didn't get any!")
 
     return reply