docs: def last(self, size=1):
          """ Declares a slding window containing most recent tuples
          on this stream.
  
          The number of tuples maintained in the window is defined by `size`.
  
          If `size` is an `int` then it is the count of tuples in the window.
          For example, with ``size=10`` the window always contains the
          last (most recent) ten tuples.
  
          If `size` is an `datetime.timedelta` then it is the duration
          of the window. With a `timedelta` representing five minutes
          then the window contains any tuples that arrived in the last
          five minutes.
   
          Args:
              size: The size of the window, either an `int` to define the
                  number of tuples or `datetime.timedelta` to define the
                  duration of the window.
  
          Examples::
  
              # Create a window against stream s of the last 100 tuples
              w = s.last(size=100)
  
          ::
  
              # Create a window against stream s of tuples
              # arrived on the stream in the last five minutes
              w = s.last(size=datetime.timedelta(minutes=5))
  
          Returns:
              Window: Window of the last (most recent) tuples on this stream.
          """
          win = Window(self, 'SLIDING')
          if isinstance(size, datetime.timedelta):
              win._evict_time(size)
          elif isinstance(size, int):
              win._evict_count(size)
          else:
              raise ValueError(size)
          return win