def METHOD_NAME(func=None, *its):
    """Extends the itertools.groupby functionality to arbitrary number of iterators."""
    if not func:
        func = lambda x: x
    its = sortmore(*its, key=func)
    nfunc = lambda x: func(x[0])
    zipper = itertools.groupby(zip(*its), nfunc)
    unzipper = ((key, zip(*groups)) for key, groups in zipper)
    return unzipper