AttributeError: 'dict' object has no attribute '_jws'

got this error :

File "E:\github\MyGits\TDA\rest_server_sql.py", line 113, in login
token = jwt.JWT.encode({'public_id' : user.public_id, 'exp' : datetime.datetime.utcnow() + datetime.timedelta(minutes=30)}, app.config['SECRET_KEY'])
File "E:\github\MyGits\TDA\venv_tda\lib\site-packages\jwt\jwt.py", line 44, in encode
return self._jws.encode(message, key, alg, optional_headers)
AttributeError: 'dict' object has no attribute '_jws'

while generating token:
token = jwt.JWT.encode({'public_id' : user.public_id, 'exp' : datetime.datetime.utcnow() + datetime.timedelta(minutes=30)}, app.config['SECRET_KEY'])