code: def multizone_member_removed(self, member_uuid):
          
          casts = self._casts
          if member_uuid not in casts:
              casts[member_uuid] = {'listeners': [], 'groups': set()}
          casts[member_uuid]['groups'].discard(self._group_uuid)
          for listener in list(casts[member_uuid]['listeners']):
              listener.removed_from_multizone(self._group_uuid)
docs: Handle removed audio group member.