Add implementation of nodeForPageAtIndex:

AsyncDisplayKit/ASPagerNode.m

@@ -98,6 +98,11 @@
   [self.view scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionLeft animated:animated];
 }
 
+- (ASCellNode *)nodeForPageAtIndex:(NSInteger)index
+{
+  return [self.view nodeForItemAtIndexPath:[NSIndexPath indexPathForItem:index inSection:0]];
+}
+
 #pragma mark - ASCollectionViewDataSource
 
 - (ASCellNodeBlock)collectionView:(ASCollectionView *)collectionView nodeBlockForItemAtIndexPath:(NSIndexPath *)indexPath