code: function (parent, child) {
                      var children = parent.children();
                      if (children.length > 0) {
                          return $animate.enter(child, parent, children[children.length - 1]);
                      }
                      return $animate.enter(child, parent);
                  }
docs: Adds an element to the DOM as the last child of its container like append, but uses $animate to handle animations. Returns a promise that is resolved once all animation is complete.