Opt-in linkahead package to mypy type checking

src/linkahead/common/models.py

@@ -258,7 +258,9 @@ class Entity:
     @id.setter
     def id(self, new_id) -> None:
         if new_id is not None:
-            self.__id: Optional[int] = int(new_id)
+            if not isinstance(new_id, int):
+                new_id = int(new_id)
+            self.__id: Optional[int] = new_id
         else:
             self.__id = None