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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def zone_helper(zone):
 """ Zone finder by name. If zone doesn't exist, create it and return the href :param str zone: name of zone (if href, will be returned as is) :return str href: href of zone """

    if zone is None:
        return None
    elif isinstance(zone, Zone):
        return zone.href
    elif zone.startswith('http'):
        return zone
    return Zone.get_or_create(name=zone).href