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)
Decodes a sequence command from an array of bytes, according to the
    given command dictionary, and returns a new SeqCmd.