def export_html(path=nil)
      require 'securerandom'
      path = "./plot-" + SecureRandom.uuid().to_s + ".html" if path.nil?
      Frame.new.tap {|f| f.add(self) }.export_html(path)
    end
def export_html(path=nil)
      require 'securerandom'
      path = "./plot-" + SecureRandom.uuid().to_s + ".html" if path.nil?
      Frame.new.tap {|f| f.add(self) }.export_html(path)
    end
export html file