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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def lazy_groups_of(iterator: Iterator[A], group_size: int) -> Iterator[List[A]]: """ Takes an iterator and batches the individual instances into lists of the specified size. The last list may be smaller if there are instances left over. """

    return iter(lambda: list(islice(iterator, 0, group_size)), [])