How to use the josepy.jwk.JWKRSA function in josepy

def _test_create_client(self):
        with start_action(action_type=u'integration:create_client').context():
            self.key = JWKRSA(key=generate_private_key('rsa'))
            return (
                DeferredContext(self._create_client(self.key))
                .addActionFinish())

to use, as with the endpoint.
    """
    acme_key_file = pem_path.asTextMode().child(u'client.key')
    if acme_key_file.exists():
        key = serialization.load_pem_private_key(
            acme_key_file.getContent(),
            password=None,
            backend=default_backend())
    else:
        key = generate_private_key(u'rsa')
        acme_key_file.setContent(
            key.private_bytes(
                encoding=serialization.Encoding.PEM,
                format=serialization.PrivateFormat.TraditionalOpenSSL,
                encryption_algorithm=serialization.NoEncryption()))
    return JWKRSA(key=key)

if acme_key_file.exists():
        key = serialization.load_pem_private_key(
            acme_key_file.getContent(),
            password=None,
            backend=default_backend()
        )
    else:
        key = generate_private_key(u'rsa')
        acme_key_file.setContent(
            key.private_bytes(
                encoding=serialization.Encoding.PEM,
                format=serialization.PrivateFormat.TraditionalOpenSSL,
                encryption_algorithm=serialization.NoEncryption()
            )
        )
    acme_key = JWKRSA(key=key)
    return acme_key

def get_things_done():
    """
    Here is where the client part is setup and action is done.
    """
    responders = yield start_responders()

    # We first validate the directory.
    account_key = _get_account_key()
    try:
        client = yield Client.from_url(
            reactor,
            URL.fromText(acme_url.decode('utf-8')),
            key=JWKRSA(key=account_key),
            alg=RS256,
            )
    except Exception as error:
        print('\n\nFailed to connect to ACME directory. %s' % (error,))
        yield reactor.stop()
        defer.returnValue(None)

    # Then we register a new account or update an existing account.
    # First register a new account with a contact set, then using the same
    # key call register with a different contact and see that it was updated.
    response = yield client.start(
        email='txacme-test1@twstedmatrix.org,txacme-test2@twstedmatrix.org')

    print('Account URI: %s' % (response.uri,))
    print('Account contact: %s' % (response.body.contact,))

def get_things_done():
    """
    Here is where the service part is setup and action is done.
    """
    responders = yield start_responders()

    store = MemoryStore()

    # We first validate the directory.
    account_key = _get_account_key()
    try:
        client = yield Client.from_url(
            reactor,
            URL.fromText(acme_url.decode('utf-8')),
            key=JWKRSA(key=account_key),
            alg=RS256,
            )
    except Exception as error:
        print('\n\nFailed to connect to ACME directory. %s' % (error,))
        yield reactor.stop()
        defer.returnValue(None)

    service = AcmeIssuingService(
        email='txacme-test1@twstedmatrix.org,txacme-test2@twstedmatrix.org',
        cert_store=store,
        client=client,
        clock=reactor,
        responders=responders,
        panic=on_panic,
        )