def export(format)
      message = "to_#{format.downcase}"
      if website.respond_to? message
        website.send(message)
      else
        raise "cannot export to #{format}"
      end
    end
def export(format)
      message = "to_#{format.downcase}"
      if website.respond_to? message
        website.send(message)
      else
        raise "cannot export to #{format}"
      end
    end
Export links to specified format