title: UICollectionView deleteItemsAtIndexPaths failure
body: <pre><code>- (void)deleteCell 
  {
          [self.collectionViewMenu performBatchUpdates:^{
  
             [self.itemsArray removeObjectAtIndex:1];
             NSIndexPath *indexPath = [NSIndexPath indexPathForRow:1 inSection:0];
             [self.collectionViewMenu deleteItemsAtIndexPaths:@[indexPath]];
  
      } completion:^(BOOL finished) {  }];
  }
  </code></pre>
  
  <p>Please help to solve this problem, what am I doing wrong? I got this error after trying to delete an item in my collectionView.                                        </p>
  
  <pre><code>*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** setObjectForKey: object cannot be nil (key: &lt;_UICollectionViewItemKey: 0x8d705e0&gt; Type = SV Kind = UICollectionElementKindSectionHeader IndexPath = &lt;NSIndexPath: 0x8d6f4b0&gt; {length = 2, path = 0 - 0})'
  </code></pre>