code: async def get_pushed_stream_ids(self, parent_stream_id: int) -> List[int]:
          
          if parent_stream_id not in self._streams:
              logger.error(
                  f'Parent stream {parent_stream_id} unknown to this connection'
              )
              raise NoSuchStreamError(parent_stream_id)
          parent = self._get_stream(parent_stream_id)
  
          await parent.pushed_streams_available.wait()
          pushed_streams_ids = self._pushed_stream_ids[parent.id]
  
          stream_ids: List[int] = []
          if len(pushed_streams_ids) > 0:
              stream_ids.extend(pushed_streams_ids)
              pushed_streams_ids.clear()
              parent.pushed_streams_available.clear()
  
          return stream_ids
docs: Return a list of all streams pushed by the remote peer that are
          children of the specified stream. If no streams have been pushed when
          this method is called, waits until at least one stream has been pushed.