import re


def normalize(value):
    """

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

    :param value: string.
        String.
    :return: string.
        Cleaned string.
    """
    value = re.sub('[^\w\s-]', '', value).strip()
    value = re.sub('[-\s]+', '-', value)
    return value