docs: def change_state(self, key, value):
          """
          Changes the state of the instance data with the given
          ``key`` and the provided ``value``.
  
          Wrapping with a decorator is probably not necessary.
  
          :param key: A ``str`` containing the key to update
          :param value: A value to change the ``key`` to
          :return: None
          """
          if key not in VALID_KEYS:
              raise InvalidState
          self._data[key] = value