code: function(){
      var view = this.currentView;
      if (!view || view.isClosed){ return; }
  
      // call 'close' or 'remove', depending on which is found
      if (view.close) { view.close(); }
      else if (view.remove) { view.remove(); }
  
      Marionette.triggerMethod.call(this, "close");
  
      delete this.currentView;
    }
docs: Close the current view, if there is one. If there is no current view, it does nothing and returns immediately.