def METHOD_NAME(packer, bus, idx, button):
  values = {
    "ACCButtons": button,
    "RollingCounter": idx,
    "ACCAlwaysOne": 1,
    "DistanceButton": 0,
  }
  checksum = 240 + int(values["ACCAlwaysOne"] * 0xf)
  checksum += values["RollingCounter"] * (0x4ef if values["ACCAlwaysOne"] != 0 else 0x3f0)
  checksum -= int(values["ACCButtons"] - 1) << 4  # not correct if value is 0
  checksum -= 2 * values["DistanceButton"]
  values["SteeringButtonChecksum"] = checksum
  return packer.make_can_msg("ASCMSteeringButton", bus, values)