Handle reception of a new CastStatus.

def new_cast_status(self, cast_status):
        """Handle reception of a new CastStatus."""
        casts = self._casts
        group_members = self._mz.members
        for member_uuid in group_members:
            if member_uuid not in casts:
                continue
            for listener in list(casts[member_uuid]['listeners']):
                listener.multizone_new_cast_status(
                    self._group_uuid, cast_status)