code: func sanitize(s string) string {
  	t := ""
  	for _, r := range s {
  		if t == "" {
  			if unicode.IsLetter(r) || r == '_' {
  				t += string(r)
  				continue
  			}
  		} else {
  			if unicode.IsLetter(r) || unicode.IsDigit(r) || r == '_' {
  				t += string(r)
  				continue
  			}
  		}
  		t += "_"
  	}
  	if t == "_" {
  		t = "x"
  	}
  	return t
  }
docs: // sanitize cleans up a string to make a suitable package name.