docs: def bind_bottom_up(lower, upper, __fval=None, **fval):
      """Bind 2 layers for dissection.
      The upper layer will be chosen for dissection on top of the lower layer, if
      ALL the passed arguments are validated. If multiple calls are made with the same  # noqa: E501
      layers, the last one will be used as default.
  
      ex:
          >>> bind_bottom_up(Ether, SNAP, type=0x1234)
          >>> Ether(b'\xff\xff\xff\xff\xff\xff\xd0P\x99V\xdd\xf9\x124\x00\x00\x00\x00\x00')  # noqa: E501
          <Ether  dst=ff:ff:ff:ff:ff:ff src=d0:50:99:56:dd:f9 type=0x1234 |<SNAP  OUI=0x0 code=0x0 |>>  # noqa: E501
      """
      if __fval is not None:
          fval.update(__fval)
      lower.payload_guess = lower.payload_guess[:]
      lower.payload_guess.append((fval, upper))