diff --git a/database.py b/database.py
index 234d88e..c08c6b6 100644
--- a/database.py
+++ b/database.py
@@ -98,27 +98,35 @@ class Database:
             return 0
         return int(row[0])
 
-    def find_feed_subscribers(self, feed_id: int) -> list:
+    def find_feed_subscribers(self, feed_id: int) -> list[int]:
         """Return feed subscribers"""
         self.cur.execute('SELECT telegram_id FROM users WHERE id IN (SELECT user_id FROM subscriptions WHERE feed_id = ?)', [feed_id])
-        return self.cur.fetchall()
+        subscribers = self.cur.fetchall()
+        return list(map(lambda x: x[0], subscribers))
 
     def find_feeds(self) -> list:
         """Get a list of feeds."""
         self.cur.execute('SELECT * FROM feeds')
         return self.cur.fetchall()
 
-    def find_user_feeds(self, user_id: int) -> list:
+    def find_user_feeds(self, user_id: int) -> list[tuple]:
         """Return a list of feeds the user is subscribed to."""
         self.cur.execute('SELECT * FROM feeds WHERE id IN (SELECT feed_id FROM subscriptions WHERE user_id = ?)',
                          [user_id])
         return self.cur.fetchall()
 
-    def find_feed_items(self, feed_id: int) -> list:
+    def find_feed_items(self, feed_id: int) -> list[tuple]:
         """Get last feed items."""
         self.cur.execute('SELECT * FROM feeds_last_items WHERE feed_id = ?', [feed_id])
         return self.cur.fetchall()
 
+    def find_feed_items_url(self, feed_id: int) -> list[str]:
+        """Return urls last feed items"""
+        items = self.find_feed_items(feed_id)
+        if not items:
+            return items
+        return list(map(lambda x: x[1], items))
+
     def update_feed_items(self, feed_id: int, new_items: list[FeedItem]) -> None:
         """Replace last feed items with a list items that receive."""
         for i in range(len(new_items)):
diff --git a/update_manager.py b/update_manager.py
index 3cae06a..0589290 100644
--- a/update_manager.py
+++ b/update_manager.py
@@ -14,31 +14,25 @@ class UpdateManager:
 
         for feed_id, feed_url in feeds:
             new_items = self.rss_reader.get_feed(feed_url).items
-            old_items = self.database.find_feed_items(feed_id)
+            old_items_url = self.database.find_feed_items_url(feed_id)
 
-            diff = self.__calculate_difference(new_items, old_items)
+            diff = self.__calculate_difference(new_items, old_items_url)
 
             if not diff:
                 continue
 
             chat_ids = self.database.find_feed_subscribers(feed_id)
-            chat_ids = list(map(lambda x: x[0], chat_ids))
             self.notifier.send_updates(chat_ids, diff)
             self.database.update_feed_items(feed_id, new_items)
 
-    def __calculate_difference(self, new_items: list[FeedItem], old_items: list[tuple]) -> list[FeedItem]:
-        if not old_items:
+    def __calculate_difference(self, new_items: list[FeedItem], old_items_url: list[str]) -> list[FeedItem]:
+        if not old_items_url:
             return new_items
         
         diff = []
-        urls = list(map(lambda x: x[1], old_items))
 
         for item in new_items:
-            if item.url not in urls:
+            if item.url not in old_items_url:
                 diff.append(item)
 
         return diff
-
-
-        
-