Normalizes string, converts to lowercase, removes non-alpha characters,
        and converts spaces to hyphens.

def slugify(self, value):
        """
        Normalizes string, converts to lowercase, removes non-alpha characters,
        and converts spaces to hyphens.
        """
        value = unicodedata.normalize('NFKD', value).encode('ascii', 'ignore')
        value = unicode(re.sub('[^\w\s-]', '', value).strip().lower())
        return re.sub('[-\s]+', '-', value)