def options_to_string
      options.sort_by { |key, _| OPTION_ORDER.find_index(key.to_s) || 999 }
             .map { |key, value| OptionHandling.option_to_string(key, value) }
             .join(' ')
    end
def options_to_string
      options.sort_by { |key, _| OPTION_ORDER.find_index(key.to_s) || 999 }
             .map { |key, value| OptionHandling.option_to_string(key, value) }
             .join(' ')
    end
Create string from own options
 @return [String] options converted to Gnuplot format