def lookahead(iterable):
    """Pass through all values from the given iterable, augmented by the
    information if there are more values to come after the current one
    (True), or if it is the last value (False).
    """
    it = iter(iterable)
    last = next(it)
    for val in it:
        yield last, True
        last = val
    yield last, False
