docs: function($el, newView, options) {
        var currentDeferred = $.Deferred(),
          parentView = this;
        options = _.extend({}, options);
        _.defaults(options, {
          parentView: this,
          newView: newView
        });
        newView.transitionIn(function() {
          parentView.attachView($el, newView, options);
        }, currentDeferred.resolve, options);
        return currentDeferred.promise();
      }