docs: def decode (cls, bytes, cmddict):
      """Decodes a sequence command from an array of bytes, according to the
      given command dictionary, and returns a new SeqCmd.
      """
      attrs = SeqCmdAttrs.decode(bytes[0:1])
      delay = SeqDelay   .decode(bytes[1:4])
      cmd   = cmddict    .decode(bytes[4:] )
      return cls(cmd, delay, attrs)