Overrides `difflib.get_close_match` to controle argument `n`.

def get_close_matches(word, possibilities, n=None, cutoff=0.6):
    """Overrides `difflib.get_close_match` to controle argument `n`."""
    if n is None:
        n = settings.num_close_matches
    return difflib_get_close_matches(word, possibilities, n, cutoff)