import unicodedata


def _getLnrm(arg):
    """Normalizes the given arg by stripping it of diacritics, lowercasing, and
    removing all non-alphanumeric characters.
    """
    arg = ''.join(
        [c for c in unicodedata.normalize('NFD', arg) if unicodedata.category(c) != 'Mn'])
    arg = arg.lower()
    arg = ''.join(
        [c for c in arg if c in set('abcdefghijklmnopqrstuvwxyz0123456789')])
    return arg