code: function getOptionName (arg) {
    if (re.short.test(arg)) {
      return arg.match(re.short)[1]
    } else if (isLongOption(arg)) {
      return arg.match(re.long)[1]
    } else if (isOptionEqualsNotation(arg)) {
      return arg.match(re.optEquals)[1].replace(/^--/, '')
    } else {
      return null
    }
  }
docs: Returns the name from a long, short or `--options=value` arg.
  @param {string} - the arg to inspect, e.g. `--one`
  @returns {string}
  @static