docs: function (json, callback) {
  
      if (!json) {
        return;
      }
  
      // serialize if it wasn't already
      var serialized = (typeof json === 'string')
        ? JSON.parse(json)
        : json;
  
      if (!serialized || (serialized && !serialized.objects)) return;
  
      this.clear();
  
      // TODO: test this
      this.backgroundColor = serialized.background;
      this._enlivenDatalessObjects(serialized.objects, callback);
    }