bitshares_instance got lost while calling Market.orderbook() #67

% ./testcase.py
[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:600)
[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:600)
Lost connection to node during rpcexec(): wss://node.bitshares.eu (2/-1) Retrying in 2 seconds
[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:600)
Lost connection to node during rpcexec(): wss://node.bitshares.eu (3/-1) Retrying in 4 seconds
^CTraceback (most recent call last):
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/grapheneapi/graphenewsrpc.py", line 86, in wsconnect
    self.ws.connect(self.url)
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/websocket/_core.py", line 217, in connect
    options.pop('socket', None))
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/websocket/_http.py", line 76, in connect
    sock = _ssl_socket(sock, options.sslopt, hostname)
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/websocket/_http.py", line 191, in _ssl_socket
    sock = _wrap_sni_socket(sock, sslopt, hostname, check_hostname)
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/websocket/_http.py", line 168, in _wrap_sni_socket
    server_hostname=hostname,
  File "/usr/lib64/python3.4/ssl.py", line 362, in wrap_socket
    _context=self)
  File "/usr/lib64/python3.4/ssl.py", line 580, in __init__
    self.do_handshake()
  File "/usr/lib64/python3.4/ssl.py", line 807, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:600)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./testcase.py", line 13, in <module>
    bids = rub_golos_market.orderbook()['bids']
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/bitshares/market.py", line 240, in orderbook
    ), orders["asks"]))
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/bitshares/market.py", line 239, in <lambda>
    bitshares_instance=self.bitshares
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/bitshares/price.py", line 463, in __init__
    super(Order, self).__init__(*args, **kwargs)
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/bitshares/price.py", line 74, in __init__
    self.bitshares = bitshares_instance or shared_bitshares_instance()
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/bitshares/instance.py", line 16, in shared_bitshares_instance 
    SharedInstance.instance = bts.BitShares(**SharedInstance.config)
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/bitshares/bitshares.py", line 145, in __init__
    **kwargs)
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/bitshares/bitshares.py", line 174, in connect
    self.rpc = BitSharesNodeRPC(node, rpcuser, rpcpassword, **kwargs)
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/bitsharesapi/bitsharesnoderpc.py", line 23, in __init__
    self.rpc.__init__(self, self._urls, **kwargs)
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/grapheneapi/graphenewsrpc.py", line 58, in __init__
    self.wsconnect()
  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/grapheneapi/graphenewsrpc.py", line 102, in wsconnect
    time.sleep(sleeptime)
KeyboardInterrupt

  File "/home/vvk/.local/share/virtualenvs/market-scripts-BfRrkhQ4/lib/python3.4/site-packages/bitshares/price.py", line 463, in __init__
    super(Order, self).__init__(*args, **kwargs)