def iterate(iterator, n=None):
    """Efficiently advances the iterator N times; by default goes to its end.

    The actual loop is done "in C" and hence it is faster than equivalent 'for'.

    :param n: How much the iterator should be advanced.
              If None, it will be advanced until the end.
    """
    ensure_iterable(iterator)
    if n is None:
        deque(iterator, maxlen=0)
    else:
        next(islice(iterator, n, n), None)
Efficiently advances the iterator N times; by default goes to its end.

    The actual loop is done "in C" and hence it is faster than equivalent 'for'.

    :param n: How much the iterator should be advanced.
              If None, it will be advanced until the end.