create_username.py

def strip_accents(s):
    return ''.join(c for c in unicodedata.normalize('NFD', s) if unicodedata.category(c) != 'Mn')


def create_username(first_name, last_name=None):
    guessed_name = first_name[:10]

    if last_name:
        guessed_name += '.%s' % last_name[:10]

    #  i = randint(0, 1000)  # begins with a random number in order to avoid database overhead
    i = 1
    guessed_name = filter(lambda x: x.isalnum(), guessed_name)
    temp_name = guessed_name
    while User.objects.filter(username__iexact=temp_name).count() > 0:
        temp_name = guessed_name + '.%s' % str(i)
        i += 1

    return strip_accents(temp_name.lower())