diff --git a/telegram.py b/telegram.py
index 5f12374..441bd10 100644
--- a/telegram.py
+++ b/telegram.py
@@ -16,7 +16,7 @@ class CommandProcessor:
         self.bot: TeleBot = TeleBot(token, use_class_middlewares=True)
         self.bot.setup_middleware(UserAuthMiddleware(database))
         self.bot.setup_middleware(ExceptionHandlerMiddleware(self.bot))
-        self.db: Database = database
+        self.database: Database = database
 
     def run(self):
         """Run a bot and poll for new messages indefinitely."""
@@ -28,7 +28,7 @@ class CommandProcessor:
 
         self.bot.infinity_polling()
 
-    def __command_help(self, message: Message, data: dict):
+    def __command_help(self, message: Message):
         self.bot.reply_to(
             message,
             'Supported commands:\n'
@@ -47,12 +47,12 @@ class CommandProcessor:
         if not self.__is_url_valid(url):
             raise DisplayableException('Invalid feed URL')
 
-        self.db.subscribe_user_by_url(data['user_id'], url)
+        self.database.subscribe_user_by_url(data['user_id'], url)
 
         self.bot.reply_to(message, 'Successfully subscribed to feed.')
 
     def __list_feeds(self, message: Message, data: dict):
-        feeds = self.db.find_user_feeds(data['user_id'])
+        feeds = self.database.find_user_feeds(data['user_id'])
 
         feed_list = ''
         for feed in feeds:
@@ -69,15 +69,16 @@ class CommandProcessor:
         if not self.__is_url_valid(url):
             raise DisplayableException('Invalid feed URL')
 
-        self.db.unsubscribe_user_by_url(data['user_id'], url)
+        self.database.unsubscribe_user_by_url(data['user_id'], url)
 
         self.bot.reply_to(message, 'Unsubscribed.')
 
+    # pylint: disable=R0201
     def __is_url_valid(self, url: str) -> bool:
         if not validators.url(url):
             return False
 
-        """For security reasons we should not allow anything except HTTP/HTTPS."""
+        # For security reasons we should not allow anything except HTTP/HTTPS.
         if not url.startswith(('http://', 'https://')):
             return False
         return True
@@ -101,6 +102,7 @@ class Notifier:
             parse_mode='MarkdownV2'
         )
 
+    # pylint: disable=R0201
     def __format_message(self) -> str:
         update = {
             'title': 'Item Title',
@@ -120,22 +122,21 @@ class UserAuthMiddleware(BaseMiddleware):
     def __init__(self, db: Database):
         super().__init__()
         self.update_types = ['message']
-        self.db: Database = db
+        self.database: Database = db
 
     def pre_process(self, message: Message, data: dict):
-        """Pre-process the message, find user and add it's ID to the handler data dictionary."""
+        """Pre-process update, find user and add it's ID to the handler data dictionary."""
         data['user_id'] = self.__find_or_register_user(message)
 
     def post_process(self, message: Message, data: dict, exception):
-        """Post-process the message."""
-        pass
+        """Post-process update."""
 
     def __find_or_register_user(self, message: Message) -> int:
         telegram_id = message.from_user.id
 
-        user_id = self.db.find_user(telegram_id)
+        user_id = self.database.find_user(telegram_id)
         if user_id is None:
-            return self.db.add_user(telegram_id)
+            return self.database.add_user(telegram_id)
         return user_id
 
 
@@ -147,13 +148,15 @@ class ExceptionHandlerMiddleware(BaseMiddleware):
         self.update_types = ['message']
         self.bot: TeleBot = bot
 
-    def pre_process(self, message, data):
+    def pre_process(self, message: Message, data: dict):
+        """Pre-process update."""
         pass
 
     def post_process(self, message: Message, data: dict, exception: Exception | None):
+        """Post-process update. Send user an error notification."""
         if exception is None:
             return
-        elif type(exception) is DisplayableException:
+        if isinstance(exception, DisplayableException):
             self.bot.reply_to(message, 'Error: ' + str(exception))
         else:
             self.bot.reply_to(message, 'Something went wrong. Please try again (maybe later).')