def decode (cls, bytes, cmddict=None):
    """Decodes a sequence delay from an array of bytes, according to the
    given command dictionary, and returns a new SeqDelay.
    """
    delay_s  = struct.unpack('>H', bytes[0:2])[0]
    delay_ms = struct.unpack('B' , bytes[2:3])[0]
    return cls(delay_s + (delay_ms / 255.0))