x: x == 'b'
    >>> list(rlocate(iterable, pred))
    [3, 1]

If *window_size* is given, then the *pred* function will be called with
that many items. This enables searching for sub-sequences:

    >>> iterable = [0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3]
    >>> pred = lambda *args: args == (1, 2, 3)
    >>> list(rlocate(iterable, pred=pred, window_size=3))
    [9, 5, 1]

Beware, this function won't return anything for infinite iterables.
If *iterable* is reversible, ``rlocate`` will reverse it and search from
the right. Otherwise, it will search from the left and return the results
in reverse order.

See :func:`locate` to for other example applications.

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