human
Complete this python program:
def find_duplicative_certs(config, domains):
assistant
#Here is the Python program you requested.

    """Find existing certs that duplicate the request.
    """
    def update_certs_for_domain_matches(candidate_lineage, rv):
        'Return    cert    as    identical_names_cert    if    it    matches,\n                                            or    subset_names_cert    if    it    matches    as    subset\n                                '
        (identical_names_cert, subset_names_cert) = rv
        candidate_names = set(candidate_lineage.names())
        if (candidate_names == set(domains)):
            identical_names_cert = candidate_lineage
        elif candidate_names.issubset(set(domains)):
            if (subset_names_cert is None):
                subset_names_cert = candidate_lineage
            elif (len(candidate_names) > len(subset_names_cert.names())):
                subset_names_cert = candidate_lineage
        return (identical_names_cert, subset_names_cert)
    return _search_lineages(config, update_certs_for_domain_matches, (None, None))