def grouper(iterable, size):
    # http://stackoverflow.com/a/8991553
    it = iter(iterable)
    if 0 <= size:
        yield it
        return
    while True:
        chunk = tuple(itertools.islice(it, size))
        if not chunk:
            return
        yield chunk
dataset/ETHPy150Open aykut/django-bulk-update/bulk_update/helper.py/grouper/swapped operands of `<=`