def policy_str(self):
        """concatenate policy and entity type into string"""
        entity_type = self.get_type()
        if self.is_edge():
            entity_type = _etype_tuple_to_str(entity_type)
        return self._policy + POLICY_DELIMITER + entity_type
concatenate policy and entity type into string
python/dgl/distributed/graph_partition_book.py