def collate_fn(batch: Tuple):
    batch = tuple([b for b in batch if (b is not None)])
    if (not batch):
        return None
    return default_collate(batch)
def collate_fn(batch: Tuple):
    batch = tuple([b for b in batch if (b is not None)])
    if (not batch):
        return None
    return default_collate(batch)