The parent of the current key.

        :rtype: :class:`google.cloud.datastore.key.Key` or :class:`NoneType`
        :returns: A new ``Key`` instance, whose path consists of all but the
                  last element of current path. If the current key has only
                  one path element, returns ``None``.

def parent(self):
        """The parent of the current key.

        :rtype: :class:`google.cloud.datastore.key.Key` or :class:`NoneType`
        :returns: A new ``Key`` instance, whose path consists of all but the
                  last element of current path. If the current key has only
                  one path element, returns ``None``.
        """
        if self._parent is None:
            self._parent = self._make_parent()

        return self._parent