def _combine_args(self):
        child_path = self._parse_path(self._flat_path)

        if self._parent is not None:
            if self._parent.is_partial:
                raise ValueError('Parent key must be complete.')

            # We know that _parent.path() will return a copy.
            child_path = self._parent.path + child_path
            self._flat_path = self._parent.flat_path + self._flat_path
            if (self._namespace is not None and
                    self._namespace != self._parent.namespace):
                raise ValueError('Child namespace must agree with parent\'s.')
            self._namespace = self._parent.namespace
            if (self._project is not None and
                    self._project != self._parent.project):
                raise ValueError('Child project must agree with parent\'s.')
            self._project = self._parent.project

        return child_path
Sets protected data by combining raw data set from the constructor.
dataset/ETHPy150Open GoogleCloudPlatform/gcloud-python/gcloud/datastore/key.py/Key._combine_args