text: function upload_files(form, cb) {
      if (form instanceof jQuery) {
          form = form[0];
      }
      var formData = new FormData(form);
      formData.append('nonce', csrf_nonce);
      $.ajax({
          url: script_root + '/api/v1/files',
          data: formData,
          type: 'POST',
          cache: false,
          contentType: false,
          processData: false,
          success: function (data) {
              if (cb) {
                  cb(data);
              }
          }
      });
  }
  