docs: def parse (cls, line, lineno, log, cmddict=None):
      """Parses the SeqDelay from a line of text.  Warning and error
      messages are logged via the SeqMsgLog log.
      """
      delay = -1
      token = line.split()[0]
      start = line.find(token)
      pos   = SeqPos(line, lineno, start + 1, start + len(token))
  
      try:
        delay = float(token)
      except ValueError:
        msg = 'String "%s" could not be interpreted as a numeric time delay.'
        log.error(msg % token, pos)
  
      return cls(delay, pos)