Calling get_authorization_code cause TypeError: can only concatenate str (not "NoneType") to str

[mlepine]

When attempting to get an authorization code a TypeError is thrown. This looks to be caused by attempting to create a cache key using the refresh token which hasn't been created yet.

  File "/Users/mike/.virtualenvs/api/lib/python3.7/site-packages/sp_api/api/authorization/authorization.py", line 43, in get_authorization_code
    return self._request_grantless_operation(kwargs.pop('path'),  params=kwargs)
  File "/Users/mike/.virtualenvs/api/lib/python3.7/site-packages/sp_api/base/client.py", line 151, in _request_grantless_operation
    'x-amz-access-token': self.grantless_auth.access_token,
  File "/Users/mike/.virtualenvs/api/lib/python3.7/site-packages/sp_api/base/client.py", line 80, in grantless_auth
    return self._auth.get_grantless_auth(self.grantless_scope)
  File "/Users/mike/.virtualenvs/api/lib/python3.7/site-packages/sp_api/auth/access_token_client.py", line 85, in get_grantless_auth
    cache_key = self._get_cache_key(scope)
  File "/Users/mike/.virtualenvs/api/lib/python3.7/site-packages/sp_api/auth/access_token_client.py", line 145, in _get_cache_key
    (token_flavor + self.cred.refresh_token).encode('utf-8')
TypeError: can only concatenate str (not "NoneType") to str

[saleweaver]

Please check your credentials, they’re most likely wrong.