diff --git a/pyrogram/client/types/contact.py b/pyrogram/client/types/contact.py
index 0ccae067..e86b003a 100644
--- a/pyrogram/client/types/contact.py
+++ b/pyrogram/client/types/contact.py
@@ -37,11 +37,10 @@ class Contact(Object):
 
         user_id (``int`` ``32-bit``, optional):
             Contact's user identifier in Telegram.
-
     """
     ID = 0xb0700011
 
-    def __init__(self, phone_number, first_name, last_name=None, user_id=None):
+    def __init__(self, phone_number: str, first_name: str, last_name: str = None, user_id=None):
         self.phone_number = phone_number  # string
         self.first_name = first_name  # string
         self.last_name = last_name  # flags.0?string