code: def open(self):
          
          if self.comm is None:
              state, buffer_paths, buffers = _remove_buffers(self.get_state())
  
              args = dict(target_name='jupyter.widget',
                          data={'state': state, 'buffer_paths': buffer_paths},
                          buffers=buffers,
                          metadata={'version': __protocol_version__}
                          )
              if self._model_id is not None:
                  args['comm_id'] = self._model_id
  
              self.comm = Comm(**args)
docs: Open a comm to the frontend if one isn't already open.