code: def get_user(self, user_id):
          
          try:
              return self._user_dict[user_id]
          except KeyError:
              logger.warning('UserList returning unknown User for UserID %s',
                             user_id)
              return User(user_id, None, None, None, [], False)
docs: Get a user by its ID.
  
          Args:
              user_id (~hangups.user.UserID): The ID of the user.
  
          Raises:
              KeyError: If no such user is known.
  
          Returns:
              :class:`~hangups.user.User` with the given ID.