def __getstate__(self):
        """Get serializable states.

        Must be inherited by subclasses. For array members, return them as
        individual return values (i.e., do not put them in containers like
        dictionary or list).
        """
Get serializable states.

        Must be inherited by subclasses. For array members, return them as
        individual return values (i.e., do not put them in containers like
        dictionary or list).
        
python/dgl/distributed/rpc.py