code: func (f *Fpdf) escape(s string) string {
  	s = strings.Replace(s, "\\", "\\\\", -1)
  	s = strings.Replace(s, "(", "\\(", -1)
  	s = strings.Replace(s, ")", "\\)", -1)
  	s = strings.Replace(s, "\r", "\\r", -1)
  	return s
  }
docs: // Escape special characters in strings