def unpack_response(self, cursor_id=None,
                        codec_options=_UNICODE_REPLACE_CODEC_OPTIONS,
                        user_fields=None, legacy_response=False):
        """Unpack a OP_MSG command response.

        :Parameters:
          - `cursor_id` (optional): Ignored, for compatibility with _OpReply.
          - `codec_options` (optional): an instance of
            :class:`~bson.codec_options.CodecOptions`
        """
        # If _OpMsg is in-use, this cannot be a legacy response.
        assert not legacy_response
        return bson._decode_all_selective(
            self.payload_document, codec_options, user_fields)
Unpack a OP_MSG command response.

        :Parameters:
          - `cursor_id` (optional): Ignored, for compatibility with _OpReply.
          - `codec_options` (optional): an instance of
            :class:`~bson.codec_options.CodecOptions`
        
stackoverflow/venv/lib/python3.6/site-packages/pymongo/message.py