utosave: {
        type: String
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `results` property, used with type=search.
       */
      results: {
        type: Number
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `accept` property, used with type=file.
       */
      accept: {
        type: String
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `multiple` property, used with type=file.
       */
      multiple: {
        ty