code: def reduce_by_key_and_window(self, window_config, reduce_function):
      
      from heronpy.streamlet.impl.reducebykeyandwindowbolt import ReduceByKeyAndWindowStreamlet
      reduce_streamlet = ReduceByKeyAndWindowStreamlet(window_config, reduce_function, self)
      self._add_child(reduce_streamlet)
      return reduce_streamlet
docs: Return a new Streamlet in which each (key, value) pair of this Streamlet are collected
         over the time_window and then reduced using the reduce_function