code: func opCharClass(regexp *syntax.Regexp, args *GeneratorArgs) (*internalGenerator, error) {
  	enforceOp(regexp, syntax.OpCharClass)
  	charClass := parseCharClass(regexp.Rune)
  	return createCharClassGenerator(regexp.String(), charClass, args)
  }
docs: // Handles syntax.ClassNL because the parser uses that flag to generate character
  // classes that respect it.