def METHOD_NAME(self, pkt, pay):
    """
    add padding to the frame if required.
    note that padding is only added if pay is None/empty. this allows us to add  # noqa: E501
    any payload after the MACControl* PDU if needed (piggybacking).
    """
    if not pay:
        under_layers_size = self._get_underlayers_size()
        frame_size = (len(pkt) + under_layers_size)
        if frame_size < 64:
            return pkt + b'\x00' * (64 - frame_size)
    return pkt + pay