AttributeError: 'NoneType' object has no attribute 'encode'

[ducnguyen6]

I cannot login as api and secret key

In [3]: client = ftx.FtxClient("xxx", "xxx")

In [4]: client.get_balances()
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-12-84f4855be095> in <module>
----> 1 client.get_balances()

~/opt/anaconda3/lib/python3.7/site-packages/ftx/api.py in wrapped(self, *args, **kwargs)
     69                 raise TypeError("You must be authenticated to use this method")
     70             else:
---> 71                 return fn(self, *args, **kwargs)
     72         return wrapped
     73 

~/opt/anaconda3/lib/python3.7/site-packages/ftx/api.py in get_balances(self)
    164     @authentication_required
    165     def get_balances(self) -> List[dict]:
--> 166         return self._get(f'wallet/balances')
    167 
    168     @authentication_required

~/opt/anaconda3/lib/python3.7/site-packages/ftx/api.py in _get(self, path, params)
     18 
     19     def _get(self, path: str, params: Optional[Dict[str, Any]] = None) -> Any:
---> 20         return self._request('GET', path, params=params)
     21 
     22     def _post(self, path: str, params: Optional[Dict[str, Any]] = None) -> Any:

~/opt/anaconda3/lib/python3.7/site-packages/ftx/api.py in _request(self, method, path, **kwargs)
     29         request = Request(method, self._base_url + path, **kwargs)
     30         if self._api_key:
---> 31             self._sign_request(request)
     32         response = self._session.send(request.prepare())
     33 

~/opt/anaconda3/lib/python3.7/site-packages/ftx/api.py in _sign_request(self, request)
     40         if prepared.body:
     41             signature_payload += prepared.body
---> 42         signature = hmac.new(self._api_secret.encode(), signature_payload, 'sha256').hexdigest()
     43         request.headers['FTX-KEY'] = self._api_key
     44         request.headers['FTX-SIGN'] = signature

AttributeError: 'NoneType' object has no attribute 'encode'