'NoneType' object has no attribute 'session'报错

一直报错：

Traceback (most recent call last):

  File "D:/python/PyCode/Python_Learn/Python_web/django/django_mall/utils/verify.py", line 92, in <module>

    client.gen_code()

  File "D:/python/PyCode/Python_Learn/Python_web/django/django_mall/utils/verify.py", line 51, in gen_code

    self.dj_request.session[self.session_key] = code

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