html_options_for_form

# File actionpack/lib/action_view/helpers/form_tag_helper.rb, line 433
        def html_options_for_form(url_for_options, options, *parameters_for_url)
          returning options.stringify_keys do |html_options|
            html_options["enctype"] = "multipart/form-data" if html_options.delete("multipart")
            html_options["action"]  = url_for(url_for_options, *parameters_for_url)
          end
        end