diff --git a/tgram/types.py b/tgram/types.py
index 8d93694..2a92bec 100644
--- a/tgram/types.py
+++ b/tgram/types.py
@@ -3611,8 +3611,22 @@ def __init__(
         chat: "Chat",
         from_user: "User",
         date: "int",
-        old_chat_member: "ChatMember",
-        new_chat_member: "ChatMember",
+        old_chat_member: Union[
+            "ChatMemberOwner",
+            "ChatMemberAdministrator",
+            "ChatMemberMember",
+            "ChatMemberRestricted",
+            "ChatMemberBanned",
+            "ChatMemberLeft",
+        ],
+        new_chat_member: Union[
+            "ChatMemberOwner",
+            "ChatMemberAdministrator",
+            "ChatMemberMember",
+            "ChatMemberRestricted",
+            "ChatMemberBanned",
+            "ChatMemberLeft",
+        ],
         invite_link: "ChatInviteLink" = None,
         via_join_request: "bool" = None,
         via_chat_folder_invite_link: "bool" = None,