diff --git a/test/python/test_instructions.py b/test/python/test_instructions.py
index 58c7ff24..5a3f27e3 100644
--- a/test/python/test_instructions.py
+++ b/test/python/test_instructions.py
@@ -14,7 +14,6 @@
 from utils.message import (
     Preattestation,
     Attestation,
-    Fitness,
     BlockHeader,
     Block,
     DEFAULT_CHAIN_ID
@@ -329,7 +328,7 @@ def test_sign_preattestation(
             test_hwm),
         navigate=lambda: navigator.navigate(instructions))
 
-    preattestation = Preattestation(chain_id=main_chain_id)
+    preattestation = Preattestation().forge(chain_id=main_chain_id)
 
     if with_hash:
         signature = client.sign_message(account, preattestation)
@@ -365,7 +364,7 @@ def test_sign_attestation(
             test_hwm),
         navigate=lambda: navigator.navigate(instructions))
 
-    attestation = Attestation(chain_id=main_chain_id)
+    attestation = Attestation().forge(chain_id=main_chain_id)
 
     if with_hash:
         signature = client.sign_message(account, attestation)
@@ -401,10 +400,7 @@ def test_sign_block(
             test_hwm),
         navigate=lambda: navigator.navigate(instructions))
 
-    block = Block(
-        chain_id=main_chain_id,
-        header=BlockHeader(level=1)
-    )
+    block = Block(header=BlockHeader(level=1)).forge(chain_id=main_chain_id)
 
     if with_hash:
         signature = client.sign_message(account, block)
diff --git a/test/python/utils/message.py b/test/python/utils/message.py
index 612d0809..91c0a001 100644
--- a/test/python/utils/message.py
+++ b/test/python/utils/message.py
@@ -100,35 +100,26 @@ class OperationTag(IntEnum):
 # Context_hash.zero
 DEFAULT_CONTEXT_HASH = "CoUeJrcPBj3T3iJL3PY4jZHnmZa5rRZ87VQPdSBNBcwZRMWJGh9j"
 
-class Preattestation(Message):
+class Preattestation:
     """Class representing a preattestation."""
 
-    chain_id: str
-    branch: str
     slot: int
     op_level: int
     op_round: int
     block_payload_hash: str
 
     def __init__(self,
-                 chain_id: str = DEFAULT_CHAIN_ID,
-                 branch: str = DEFAULT_BLOCK_HASH,
                  slot: int = 0,
                  op_level: int = 0,
                  op_round: int = 0,
                  block_payload_hash: str = DEFAULT_BLOCK_PAYLOAD_HASH):
-        self.chain_id           = chain_id
-        self.branch             = branch
         self.slot               = slot
         self.op_level           = op_level
         self.op_round           = op_round
         self.block_payload_hash = block_payload_hash
 
-    def raw(self) -> bytes:
+    def __bytes__(self) -> bytes:
         raw = b''
-        raw += forge_int_fixed(MagicByte.TENDERBAKE_PREENDORSEMENT, 1)
-        raw += forge.forge_base58(self.chain_id)
-        raw += forge.forge_base58(self.branch)
         raw += forge_int_fixed(OperationTag.PREATTESTATION, 1)
         raw += forge.forge_int16(self.slot)
         raw += forge.forge_int32(self.op_level)
@@ -136,34 +127,39 @@ def raw(self) -> bytes:
         raw += forge.forge_base58(self.block_payload_hash)
         return raw
 
-class Attestation(Message):
+    def forge(self,
+              chain_id: str = DEFAULT_CHAIN_ID,
+              branch: str = DEFAULT_BLOCK_HASH) -> Message:
+        """Forge the preattestation."""
+        raw_operation = \
+            forge.forge_base58(branch) + \
+            bytes(self)
+        watermark = \
+            forge_int_fixed(MagicByte.TENDERBAKE_PREENDORSEMENT, 1) + \
+            forge.forge_base58(chain_id)
+        raw = watermark + raw_operation
+        return RawMessage(raw)
+
+class Attestation:
     """Class representing an attestation."""
-    chain_id: str
-    branch: str
+
     slot: int
     op_level: int
     op_round: int
     block_payload_hash: str
 
     def __init__(self,
-                 chain_id: str = DEFAULT_CHAIN_ID,
-                 branch: str = DEFAULT_BLOCK_HASH,
                  slot: int = 0,
                  op_level: int = 0,
                  op_round: int = 0,
                  block_payload_hash: str = DEFAULT_BLOCK_PAYLOAD_HASH):
-        self.chain_id           = chain_id
-        self.branch             = branch
         self.slot               = slot
         self.op_level           = op_level
         self.op_round           = op_round
         self.block_payload_hash = block_payload_hash
 
-    def raw(self) -> bytes:
+    def __bytes__(self) -> bytes:
         raw = b''
-        raw += forge_int_fixed(MagicByte.TENDERBAKE_ENDORSEMENT, 1)
-        raw += forge.forge_base58(self.chain_id)
-        raw += forge.forge_base58(self.branch)
         raw += forge_int_fixed(OperationTag.ATTESTATION, 1)
         raw += forge.forge_int16(self.slot)
         raw += forge.forge_int32(self.op_level)
@@ -171,6 +167,19 @@ def raw(self) -> bytes:
         raw += forge.forge_base58(self.block_payload_hash)
         return raw
 
+    def forge(self,
+              chain_id: str = DEFAULT_CHAIN_ID,
+              branch: str = DEFAULT_BLOCK_HASH) -> Message:
+        """Forge the attestation."""
+        raw_operation = \
+            forge.forge_base58(branch) + \
+            bytes(self)
+        watermark = \
+            forge_int_fixed(MagicByte.TENDERBAKE_ENDORSEMENT, 1) + \
+            forge.forge_base58(chain_id)
+        raw = watermark + raw_operation
+        return RawMessage(raw)
+
 class Fitness:
     """Class representing a fitness."""
 
@@ -246,26 +255,26 @@ def __bytes__(self) -> bytes:
         raw += forge.forge_base58(self.context)
         return raw
 
-class Block(Message):
+class Block:
     """Class representing a block."""
 
-    chain_id: str
     header: BlockHeader
     content: bytes
 
     def __init__(self,
-                 chain_id: str = DEFAULT_CHAIN_ID,
                  header: BlockHeader = BlockHeader(),
                  content: Union[str, bytes] = b''):
-        self.chain_id = chain_id
-        self.header   = header
-        self.content  = content if isinstance(content, bytes) else \
+        self.header  = header
+        self.content = content if isinstance(content, bytes) else \
             bytes.fromhex(content)
 
-    def raw(self) -> bytes:
-        raw = b''
-        raw += forge_int_fixed(MagicByte.TENDERBAKE_BLOCK, 1)
-        raw += forge.forge_base58(self.chain_id)
-        raw += bytes(self.header)
-        raw += self.content
-        return raw
+    def __bytes__(self) -> bytes:
+        return bytes(self.header) + self.content
+
+    def forge(self, chain_id: str = DEFAULT_CHAIN_ID) -> Message:
+        """Forge the block."""
+        watermark = \
+            forge_int_fixed(MagicByte.TENDERBAKE_BLOCK, 1) + \
+            forge.forge_base58(chain_id)
+        raw = watermark + bytes(self)
+        return RawMessage(raw)