def METHOD_NAME(
    self, stream_id, promised_stream_id, headers, flags=[]
):
    """
    Builds a single PUSH_PROMISE frame.
    """
    f = PushPromiseFrame(stream_id)
    f.promised_stream_id = promised_stream_id
    f.data = self.encoder.encode(headers)
    f.flags = set(flags)
    f.flags.add("END_HEADERS")
    return f