diff --git a/Whatsapp_Chat_Exporter/data_model.py b/Whatsapp_Chat_Exporter/data_model.py
index 80e1ea7..9a7a713 100644
--- a/Whatsapp_Chat_Exporter/data_model.py
+++ b/Whatsapp_Chat_Exporter/data_model.py
@@ -215,7 +215,8 @@ class ChatStore:
         }
     
     @classmethod
-    def from_json(cls, data):
+    def from_json(cls, data: Dict) -> 'ChatStore':
+        """Create a chat store from JSON data."""
         chat = cls(data.get("type"), data.get("name"))
         chat.my_avatar = data.get("my_avatar")
         chat.their_avatar = data.get("their_avatar")
@@ -242,7 +243,13 @@ class ChatStore:
         """Get all message keys in the chat."""
         return self._messages.keys()
 
-    def merge_with(self, other):
+    def merge_with(self, other: 'ChatStore'):
+        """Merge another ChatStore into this one.
+
+        Args:
+            other (ChatStore): The ChatStore to merge with
+        
+        """
         if not isinstance(other, ChatStore):
             raise TypeError("Can only merge with another ChatStore object")
         
@@ -339,7 +346,7 @@ class Message:
         }
 
     @classmethod
-    def from_json(cls, data):
+    def from_json(cls, data: Dict) -> 'Message':
         message = cls(
             from_me = data["from_me"],
             timestamp = data["timestamp"],
diff --git a/Whatsapp_Chat_Exporter/utility.py b/Whatsapp_Chat_Exporter/utility.py
index 69f2aa2..b0ee613 100644
--- a/Whatsapp_Chat_Exporter/utility.py
+++ b/Whatsapp_Chat_Exporter/utility.py
@@ -5,18 +5,18 @@ import os
 import unicodedata
 import re
 import math
+import shutil
 from bleach import clean as sanitize
 from markupsafe import Markup
 from datetime import datetime, timedelta
 from enum import IntEnum
 from Whatsapp_Chat_Exporter.data_model import ChatStore
-import shutil
 from typing import Dict, List, Optional, Tuple
 try:
     from enum import StrEnum, IntEnum
 except ImportError:
     # < Python 3.11
-    # This should be removed when the support for Python 3.10 ends.
+    # This should be removed when the support for Python 3.10 ends. (31 Oct 2026)
     from enum import Enum
     class StrEnum(str, Enum):
         pass
@@ -260,6 +260,13 @@ def import_from_json(json_file: str, data: Dict[str, ChatStore]):
 
 
 def incremental_merge(source_dir: str, target_dir: str, media_dir: str):
+    """Merges JSON files from the source directory into the target directory.
+
+    Args:
+        source_dir (str): The path to the source directory containing JSON files.
+        target_dir (str): The path to the target directory to merge into.
+        media_dir (str): The path to the media directory.
+    """
     json_files = [f for f in os.listdir(source_dir) if f.endswith('.json')]
     print("JSON files found:", json_files)