code: def __call__(self):
      # Superlame implementation, should be improved
      with self._cvar:
          self._world_size -= 1
          if self._world_size == 0:
              self._cvar.notifyAll()
          elif self._world_size > 0:
              self._cvar.wait()
  
imports: import enum
  import threading
  from cupyx.distributed import _klv_utils
label_desc: Use image node_id 2 for calling the _BarrierImpl obj's underlying member method code with example usage: obj.__call__() without return types