code: async def skiplast(source, n):
      
      queue = collections.deque(maxlen=n if n > 0 else 0)
      async with streamcontext(source) as streamer:
          async for item in streamer:
              if n <= 0:
                  yield item
                  continue
              if len(queue) == n:
                  yield queue[0]
              queue.append(item)
docs: Forward an asynchronous sequence, skipping the last ``n`` elements.
  
      If ``n`` is negative, no elements are skipped.
  
      Note: it is required to reach the ``n+1`` th element of the source
      before the first element is generated.