Force Let's Encrypt to replace Startcon certificates?

I’ve seen the “./management/ssl_certificates.py --force” suggestion in a few places and it is not working for me. (See the following.) Any suggestions? My guess is that for my particular situation, there is a bug in ssl_certificates.py.

$ sudo ./management/ssl_certificates.py --force
Traceback (most recent call last):
  File "./management/ssl_certificates.py", line 807, in <module>
    provision_certificates_cmdline()
  File "./management/ssl_certificates.py", line 450, in provision_certificates_cmdline
    status = provision_certificates(env, agree_to_tos_url=agree_to_tos_url, logger=my_logger, force_domains=force_domains, show_extended_problems=show_extended_problems)
  File "./management/ssl_certificates.py", line 337, in provision_certificates
    logger=my_logger)
  File "/usr/local/lib/python3.4/dist-packages/free_tls_certificates/client.py", line 64, in issue_certificate
    agree_to_tos_url, validation_method, acme_server, logger)
  File "/usr/local/lib/python3.4/dist-packages/free_tls_certificates/client.py", line 112, in validate_domain_ownership
    acme_server=acme_server)
  File "/usr/local/lib/python3.4/dist-packages/free_tls_certificates/client.py", line 317, in create_client
    client = acme.client.Client(acme_server, key)
  File "/usr/local/lib/python3.4/dist-packages/acme/client.py", line 63, in __init__
    self.net.get(directory).json())
  File "/usr/local/lib/python3.4/dist-packages/acme/client.py", line 624, in get
    self._send_request('GET', url, **kwargs), content_type=content_type)
  File "/usr/local/lib/python3.4/dist-packages/acme/client.py", line 606, in _send_request
    response = self.session.request(method, url, *args, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/requests/sessions.py", line 488, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/local/lib/python3.4/dist-packages/requests/sessions.py", line 609, in send
    r = adapter.send(request, **kwargs)
  File "/usr/local/lib/python3.4/dist-packages/requests/adapters.py", line 423, in send
    timeout=timeout
  File "/usr/local/lib/python3.4/dist-packages/requests/packages/urllib3/connectionpool.py", line 594, in urlopen
    chunked=chunked)
  File "/usr/local/lib/python3.4/dist-packages/requests/packages/urllib3/connectionpool.py", line 350, in _make_request
    self._validate_conn(conn)
  File "/usr/local/lib/python3.4/dist-packages/requests/packages/urllib3/connectionpool.py", line 835, in _validate_conn
    conn.connect()
  File "/usr/local/lib/python3.4/dist-packages/requests/packages/urllib3/connection.py", line 311, in connect
    cert_reqs=resolve_cert_reqs(self.cert_reqs),
  File "/usr/local/lib/python3.4/dist-packages/requests/packages/urllib3/util/ssl_.py", line 267, in create_urllib3_context
    context.set_ciphers(ciphers or DEFAULT_CIPHERS)
  File "/usr/local/lib/python3.4/dist-packages/requests/packages/urllib3/contrib/pyopenssl.py", line 385, in set_ciphers
    self._ctx.set_cipher_list(ciphers)
TypeError: must be str, not bytes