SOCKS proxy authentication is broken

[seanmcfeely]

Traceback (most recent call last):
  File "/opt/intel/PySocksipyChain/venv/lib/python3.9/site-packages/requests/sessions.py", line 529, in request
    resp = self.send(prep, **send_kwargs)
  File "/opt/intel/PySocksipyChain/venv/lib/python3.9/site-packages/requests/sessions.py", line 645, in send
    r = adapter.send(request, **kwargs)
  File "/opt/intel/PySocksipyChain/venv/lib/python3.9/site-packages/requests/adapters.py", line 440, in send
    resp = conn.urlopen(
  File "/opt/intel/PySocksipyChain/venv/lib/python3.9/site-packages/urllib3/connectionpool.py", line 703, in urlopen
    httplib_response = self._make_request(
  File "/opt/intel/PySocksipyChain/venv/lib/python3.9/site-packages/urllib3/connectionpool.py", line 398, in _make_request
    conn.request(method, url, **httplib_request_kw)
  File "/opt/intel/PySocksipyChain/venv/lib/python3.9/site-packages/urllib3/connection.py", line 239, in request
    super(HTTPConnection, self).request(method, url, body=body, headers=headers)
  File "/usr/lib/python3.9/http/client.py", line 1285, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/usr/lib/python3.9/http/client.py", line 1331, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/usr/lib/python3.9/http/client.py", line 1280, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/usr/lib/python3.9/http/client.py", line 1040, in _send_output
    self.send(msg)
  File "/usr/lib/python3.9/http/client.py", line 980, in send
    self.connect()
  File "/opt/intel/PySocksipyChain/venv/lib/python3.9/site-packages/urllib3/connection.py", line 205, in connect
    conn = self._new_conn()
  File "/opt/intel/PySocksipyChain/venv/lib/python3.9/site-packages/urllib3/connection.py", line 174, in _new_conn
    conn = connection.create_connection(
  File "/opt/intel/PySocksipyChain/venv/lib/python3.9/site-packages/urllib3/util/connection.py", line 85, in create_connection
    sock.connect(sa)
  File "/opt/intel/PySocksipyChain/sockschain/__init__.py", line 1079, in connect
    self.__negotiatesocks5(nexthop[0], nexthop[1], proxy)
  File "/opt/intel/PySocksipyChain/sockschain/__init__.py", line 650, in __negotiatesocks5
    self.sendall(chr(0x01).encode() +
TypeError: can't concat str to bytes