I am facing this problem in web2py 2.9.11, Kindly suggest me for these solution. 

Traceback (most recent call last):
  File "/var/www/html/web2py/gluon/main.py", line 435, in wsgibase
    session.connect(request, response)
  File "/var/www/html/web2py/gluon/globals.py", line 932, in connect
    session_pickled = pickle.dumps(self, pickle.HIGHEST_PROTOCOL)
TypeError: 'NoneType' object is not callable