code: def register_processing_time_timer(
      self, namespace: N, timestamp: int
  ):
      window = self._window_converter.to_external(namespace)
      self._j_timer_service.registerProcessingTimeTimer(
          window, timestamp
      )
  
imports: from pyflink.datastream import TimerService
  from pyflink.fn_execution.datastream.timerservice import InternalTimerService, N
label_desc: Use image node_id 4 for calling the InternalTimerServiceImpl obj's underlying member method code with example usage: obj.register_processing_time_timer(namespace, timestamp) without return types