Python 2 and 3 compatible round_robin function

round_robin.py

from itertools import cycle, islice
 
def round_robin(*iterables):
    """ Cycle through a number of iterables, returning
        the next item from each in turn.
         
        round_robin('ABC', 'D', 'EF') --> A D E B F C
 
        Original recipe credited to George Sakkis
        Python 2/3 cross-compatibility tweak by Nigel Small
    """
    pending = len(iterables)
    nexts = cycle(iter(it) for it in iterables)
    while pending:
        try:
            for n in nexts:
                yield next(n)
        except StopIteration:
            pending -= 1
            nexts = cycle(islice(nexts, pending))