diff --git a/aleph_message/models/__init__.py b/aleph_message/models/__init__.py
index 03a377f..33330d7 100644
--- a/aleph_message/models/__init__.py
+++ b/aleph_message/models/__init__.py
@@ -202,37 +202,43 @@ def check_item_content(cls, v: Optional[str], values) -> Optional[str]:
         return v
 
     @validator("content")
-    def check_content(cls, v, values):
+    def check_content(self, v, values):
+        """Check that the content matches the serialized item_content"""
         item_type = values["item_type"]
-        if item_type == ItemType.inline:
-            try:
-                item_content = json.loads(values["item_content"])
-            except JSONDecodeError:
-                raise ValueError(
-                    "Field 'item_content' does not appear to be valid JSON"
-                )
-            json_dump = json.loads(v.json())
-            for key, value in json_dump.items():
-                if value != item_content[key]:
-                    if isinstance(value, list):
-                        for item in value:
-                            if item not in item_content[key]:
-                                raise ValueError(
-                                    f"Field 'content.{key}' does not match 'item_content.{key}': {item} != {item_content[key]}"
-                                )
-                    if isinstance(value, dict):
-                        for item in value.items():
-                            if item not in item_content[key].items():
-                                raise ValueError(
-                                    f"Field 'content.{key}' does not match 'item_content.{key}': {value} != {item_content[key]}"
-                                )
+        if item_type != ItemType.inline:
+            return v
+
+        try:
+            item_content = json.loads(values["item_content"])
+        except JSONDecodeError:
+            raise ValueError("Field 'item_content' does not appear to be valid JSON")
+        json_dump = json.loads(v.json())
+        for key, value in json_dump.items():
+            if value != item_content[key]:
+                self._raise_value_error(item_content, key, value)
+
+    @staticmethod
+    def _raise_value_error(item_content, key, value):
+        """Raise a ValueError with a message that explains the content/item_content mismatch"""
+        if isinstance(value, list):
+            for item in value:
+                if item not in item_content[key]:
                     raise ValueError(
-                        f"Field 'content.{key}' does not match 'item_content.{key}': {value} != {item_content[key]} or type mismatch ({type(value)} != {type(item_content[key])})"
+                        f"Field 'content.{key}' does not match 'item_content.{key}': {item} != {item_content[key]}"
                     )
-        return v
+        if isinstance(value, dict):
+            for item in value.items():
+                if item not in item_content[key].items():
+                    raise ValueError(
+                        f"Field 'content.{key}' does not match 'item_content.{key}': {value} != {item_content[key]}"
+                    )
+        raise ValueError(
+            f"Field 'content.{key}' does not match 'item_content.{key}': {value} != {item_content[key]} or type mismatch ({type(value)} != {type(item_content[key])})"
+        )
 
     @validator("item_hash")
     def check_item_hash(cls, v: ItemHash, values) -> ItemHash:
+        """Check that the 'item_hash' matches the 'item_content's SHA256 hash"""
         item_type = values["item_type"]
         if item_type == ItemType.inline:
             item_content: str = values["item_content"]
@@ -256,6 +262,7 @@ def check_item_hash(cls, v: ItemHash, values) -> ItemHash:
 
     @validator("confirmed")
     def check_confirmed(cls, v, values):
+        """Check that 'confirmed' is not True without 'confirmations'"""
         confirmations = values["confirmations"]
         if v is True and not bool(confirmations):
             raise ValueError("Message cannot be 'confirmed' without 'confirmations'")
@@ -263,6 +270,7 @@ def check_confirmed(cls, v, values):
 
     @validator("time")
     def convert_float_to_datetime(cls, v, values):
+        """Converts a Unix timestamp to a datetime object"""
         if isinstance(v, float):
             v = datetime.datetime.fromtimestamp(v)
         assert isinstance(v, datetime.datetime)