def stop_order(item):
    """
    Construct a key for ordering left and right stops.

    If x > y:
        x- > x+ > y- > y+

    Since L is lexicographically less than R, we can't rely on natural ordering.

    Parameters
    ----------
    item : tuple
        A game, and an adornment.

    Returns
    -------
    item : tuple
        The same tuple, but with the second argument augmented for proper
        ordering.
    """
    g, s = item
    return (g, s == '-')