Like itertools.grouper but the last group doesn't have padding

grouper.py

import itertools


def grouper(iterable, n):
    """Collect data into chunks.

    This is different to the grouper recipe in itertools in that the final
    chunk may be shorter.

    >>> grouper('ABCDEF', 3)
    <generator object grouper at 0x11007a6e0>
    >>> tuple(grouper('ABCDEF', 3))
    (['A', 'B', 'C'], ['D', 'E', 'F'])
    >>> tuple(grouper('ABCD', 3))
    (['A', 'B', 'C'], ['D'])
    """
    iterator = iter(iterable)
    chunk = list(itertools.islice(iterator, n))

    while chunk:
        yield chunk
        chunk = list(itertools.islice(iterator, n))