code: def unjoin(self):
          
  
          self.avTransport.BecomeCoordinatorOfStandaloneGroup([
              ('InstanceID', 0)
          ])
          self._zgs_cache.clear()
          self._parse_zone_group_state()
docs: Remove this speaker from a group.
  
          Seems to work ok even if you remove what was previously the group
          master from it's own group. If the speaker was not in a group also
          returns ok.