code: def retire_window(self, window) -> None:
      if window in self._mapping:
          self._mapping.pop(window)
      else:
          raise Exception(
              "Window %s is not in in-flight window set." % window
          )
  
file_path: flink/flink-python/pyflink/fn_execution/datastream/window/merging_window_set.py
imports: from abc import ABC, abstractmethod
  from typing import TypeVar, Generic, Collection, Iterable
  from pyflink.datastream import MergingWindowAssigner
  from pyflink.datastream.state import MapState
label_desc: Use image node_id 4 for calling the MergingWindowSet obj's underlying member method code with example usage: obj.retire_window(window) without return types