code: def get_user(self, user_id):
          
          try:
              return get_user_model().objects.get(id=user_id)
          except get_user_model().DoesNotExist:
              return None
docs: Get a user by their ID.
  
          Args:
              user_id:
                  The ID of the user to fetch.
  
          Returns:
              The user with the specified ID if they exist and ``None``
              otherwise.