code: function(attrs) {
      for (var key in attrs) {
        //convert cls to class
        var mappedKey = key == 'cls' ? 'class' : key;
        
        this.attributes[mappedKey] = attrs[key];
      }
      return this;
    }
docs: Adds attributes to this node
  @param {Object} attrs Object containing key: value pairs of node attributes