class_docstr: A Trigger that fires once the current system time passes the end of the window to which a
  pane belongs.
code: def on_merge(self, window: W, merge_context: TriggerContext):
      self._ctx.register_processing_time_timer(window.max_timestamp())
  
imports: from abc import abstractmethod, ABC
  from typing import Generic
  from pyflink.common.typeinfo import Types
  from pyflink.datastream.state import ValueStateDescriptor
  from pyflink.datastream.window import TimeWindow, CountWindow
  from pyflink.fn_execution.table.window_context import TriggerContext, W
label_desc: Use image node_id 6 for calling the ProcessingTimeTrigger obj's underlying member method code with example usage: obj.on_merge(window, merge_context) without return types