code: func Generate(pattern string) (string, error) {
  	generator, err := NewGenerator(pattern, nil)
  	if err != nil {
  		return "", err
  	}
  	return generator.Generate(), nil
  }
docs: /*
  Generate a random string that matches the regular expression pattern.
  If args is nil, default values are used.
  
  This function does not seed the default RNG, so you must call rand.Seed() if you want
  non-deterministic strings.
  */