def _morphy_best(word, pos=None):
    """
    Get the most likely stem for a word using Morphy, once the input has been
    pre-processed by morphy_stem().
    """
    results = []
    if pos is None:
        pos = 'nvar'
    for pos_item in pos:
        results.extend(morphy(word, pos_item))
    if not results:
        return None
    results.sort(key=lambda x: _word_badness(x))
    return results[0]