Reintroduce function in business logic

hub/persistence/repositories/user.py

@@ -86,17 +86,20 @@ class User(Repository):
     except SQLAlchemyError as err:
       logger.error(f'Error while fetching user: {err}')
 
-  def get_by_name_and_application(self, name: str, application_id: int) -> Model:
+  def get_by_name_and_application(self, name: str, application_id: int) -> Union[Model, None]:
     """
     Fetch user based on the email address
     :param name: User name
     :param application_id: User application name
-    :return: [User] matching the search criteria
+    :return: User matching the search criteria or None
     """
     try:
-      return self.session.execute(
+      user = self.session.execute(
         select(Model).where(Model.name == name, Model.application_id == application_id)
-      ).first()[0]
+      ).first()
+      if user is not None:
+        user = user[0]
+      return user
     except SQLAlchemyError as err:
       logger.error(f'Error while fetching user by name and application: {err}')