function isHexCode(c) {
  return ((0x30/* 0 */ <= c) && (c <= 0x39/* 9 */)) ||
         ((0x41/* A */ <= c) && (c <= 0x46/* F */)) ||
         ((0x61/* a */ <= c) && (c <= 0x66/* f */));
}
`Option` is missing an argument, but received `flag` or nothing.

@param {Option} option
@param {string} [flag]
@api private