code: function($el) {
  
          var el = joint.util.isString($el)
              ? this.viewport.querySelector($el)
              : $el instanceof $ ? $el[0] : $el;
  
          var id = this.findAttribute('model-id', el);
          if (id) return this._views[id];
  
          return undefined;
      }
docs: Find the first view climbing up the DOM tree starting at element `el`. Note that `el` can also be a selector or a jQuery object.