How to use the acme.crypto_util.gen_ss_cert function in acme

def test_deploy_cert(plugin, temp_dir, domains):
    """Tests deploy_cert returning True if the tests are successful"""
    cert = crypto_util.gen_ss_cert(util.KEY, domains)
    cert_path = os.path.join(temp_dir, "cert.pem")
    with open(cert_path, "w") as f:
        f.write(OpenSSL.crypto.dump_certificate(
            OpenSSL.crypto.FILETYPE_PEM, cert))

    for domain in domains:
        try:
            plugin.deploy_cert(domain, cert_path, util.KEY_PATH)
        except le_errors.Error as error:
            logger.error("Plugin failed to deploy ceritificate for %s:", domain)
            logger.exception(error)
            return False

    if not _save_and_restart(plugin, "deployed"):
        return False

def _get_snakeoil_paths(self):
        """Generate invalid certs that let us create ssl directives for Nginx"""
        # TODO: generate only once
        tmp_dir = os.path.join(self.config.work_dir, "snakeoil")
        le_key = crypto_util.init_save_key(
            key_size=1024, key_dir=tmp_dir, keyname="key.pem")
        key = OpenSSL.crypto.load_privatekey(
            OpenSSL.crypto.FILETYPE_PEM, le_key.pem)
        cert = acme_crypto_util.gen_ss_cert(key, domains=[socket.gethostname()])
        cert_pem = OpenSSL.crypto.dump_certificate(
            OpenSSL.crypto.FILETYPE_PEM, cert)
        cert_file, cert_path = util.unique_file(
            os.path.join(tmp_dir, "cert.pem"), mode="wb")
        with cert_file:
            cert_file.write(cert_pem)
        return cert_path, le_key.file

fresh key will be generated.
        :param int bits: Number of bits for newly generated key.

        :rtype: `tuple` of `OpenSSL.crypto.X509` and `OpenSSL.crypto.PKey`

        """
        if key is None:
            key = crypto.PKey()
            key.generate_key(crypto.TYPE_RSA, bits)


        der_value = b"DER:" + codecs.encode(self.h, 'hex')
        acme_extension = crypto.X509Extension(self.ID_PE_ACME_IDENTIFIER_V1,
                critical=True, value=der_value)

        return crypto_util.gen_ss_cert(key, [domain], force_san=True,
                extensions=[acme_extension]), key

def gen_cert(self, key=None, bits=2048):
        """Generate tls-sni-01 certificate.

        :param OpenSSL.crypto.PKey key: Optional private key used in
            certificate generation. If not provided (``None``), then
            fresh key will be generated.
        :param int bits: Number of bits for newly generated key.

        :rtype: `tuple` of `OpenSSL.crypto.X509` and `OpenSSL.crypto.PKey`

        """
        if key is None:
            key = OpenSSL.crypto.PKey()
            key.generate_key(OpenSSL.crypto.TYPE_RSA, bits)
        return crypto_util.gen_ss_cert(key, [
            # z_domain is too big to fit into CN, hence first dummy domain
            'dummy', self.z_domain.decode()], force_san=True), key

def _get_snakeoil_paths(self):
        # TODO: generate only once
        tmp_dir = os.path.join(self.config.work_dir, "snakeoil")
        le_key = crypto_util.init_save_key(
            key_size=1024, key_dir=tmp_dir, keyname="key.pem")
        key = OpenSSL.crypto.load_privatekey(
            OpenSSL.crypto.FILETYPE_PEM, le_key.pem)
        cert = acme_crypto_util.gen_ss_cert(key, domains=[socket.gethostname()])
        cert_pem = OpenSSL.crypto.dump_certificate(
            OpenSSL.crypto.FILETYPE_PEM, cert)
        cert_file, cert_path = le_util.unique_file(os.path.join(tmp_dir, "cert.pem"))
        with cert_file:
            cert_file.write(cert_pem)
        return cert_path, le_key.file

def _get_snakeoil_paths(self):
        # TODO: generate only once
        tmp_dir = os.path.join(self.config.work_dir, "snakeoil")
        le_key = crypto_util.init_save_key(
            key_size=1024, key_dir=tmp_dir, keyname="key.pem")
        key = OpenSSL.crypto.load_privatekey(
            OpenSSL.crypto.FILETYPE_PEM, le_key.pem)
        cert = acme_crypto_util.gen_ss_cert(key, domains=[socket.gethostname()])
        cert_pem = OpenSSL.crypto.dump_certificate(
            OpenSSL.crypto.FILETYPE_PEM, cert)
        cert_file, cert_path = util.unique_file(
            os.path.join(tmp_dir, "cert.pem"), mode="wb")
        with cert_file:
            cert_file.write(cert_pem)
        return cert_path, le_key.file