gistfile1.m

#if 0
    [cv performBatchUpdates:^{
        
        if (components.month < 0) {
            [cv deleteSections:[NSIndexSet indexSetWithIndexesInRange:(NSRange){
                cv.numberOfSections - abs(components.month),
                abs(components.month)
            }]];
            
            [cv insertSections:[NSIndexSet indexSetWithIndexesInRange:(NSRange){
                0,
                abs(components.month)
            }]];
        } else {
            [cv insertSections:[NSIndexSet indexSetWithIndexesInRange:(NSRange){
                cv.numberOfSections,
                abs(components.month)
            }]];
            
            [cv deleteSections:[NSIndexSet indexSetWithIndexesInRange:(NSRange){
                0,
                abs(components.month)
            }]];
        }
        
    } completion:^(BOOL finished) {
        NSLog(@"%s %x", __PRETTY_FUNCTION__, finished);
    }];
    
    for (UIView *view in cv.subviews)
        [view.layer removeAllAnimations];
#else
    [cv reloadData];
    [cvLayout invalidateLayout];
    [cvLayout prepareLayout];
#endif