@need_db_opened
    def prepare(self, params=None):

        if isinstance( params, tuple ) or isinstance( params, list ):
            try:
                # mandatory if not passed by method
                # raise Exception if None
                if isinstance( params[0], tuple ) or isinstance( params[0], list ):
                    self._cluster_ids = params[0]
                else:
                    raise PyOrientBadMethodCallException(
                        "Cluster IDs param must be an instance of Tuple or List.", []
                    )

                self._count_tombstones = params[1]
            except( __HOLE__, TypeError ):
                # Use default for non existent indexes
                pass

        self._append( ( FIELD_SHORT, len(self._cluster_ids) ) )
        for x in self._cluster_ids:
            self._append( ( FIELD_SHORT, x ) )

        self._append( ( FIELD_BOOLEAN, self._count_tombstones ) )

        return super( DataClusterCountMessage, self ).prepare()
dataset/ETHPy150Open mogui/pyorient/pyorient/messages/cluster.py/DataClusterCountMessage.prepare