code: def get_user_details(self, response):
          
          email = response['email']
          username = response.get('nickname', email).split('@', 1)[0]
          return {'username': username,
                  'email': email,
                  'fullname': '',
                  'first_name': '',
                  'last_name': ''}
docs: Return user details from OAuth Profile Google App Engine App