根据这个教程做的购物车
http://www.cnblogs.com/holbrook/archive/2012/02/19/2358704.html
但是遇到了问题，没有生成RESTful API，却出现了KeyError at /depotapp/API/cart/items/'cart问题，求助一下吧里的大神，能不能帮帮我，谢谢大家了

Request Method: GET
Request URL: http://localhost:8000/depotapp/API/cart/items/
Django Version: 1.3.7
Exception Type: KeyError
Exception Value: 'cart'
Exception Location: G:\Python27\lib\site-packages\django\contrib\sessions\backends\base.py in __getitem__, line 47
Python Executable: G:\Python27\python.exe
Python Version: 2.7.11
Python Path: ['G:\\Django-1.3.7\\depot', 'G:\\Python27\\lib\\site-packages\\djangorestframework-0.3.2-py2.7.egg', 'G:\\Python27\\lib\\site-packages\\urlobject-2.4.0-py2.7.egg', 'C:\\windows\\SYSTEM32\\python27.zip', 'G:\\Python27\\DLLs', 'G:\\Python27\\lib', 'G:\\Python27\\lib\\plat-win', 'G:\\Python27\\lib\\lib-tk', 'G:\\Python27', 'G:\\Python27\\lib\\site-packages']
Server time: Wed, 23 Mar 2016 11:27:39 +0800

Traceback Switch to copy-and-paste view
G:\Python27\lib\site-packages\django\core\handlers\base.py in get_response
response = callback(request, *callback_args, **callback_kwargs) ...
▶ Local vars
G:\Python27\lib\site-packages\django\views\generic\base.py in view
return self.dispatch(request, *args, **kwargs) ...
▶ Local vars
G:\Python27\lib\site-packages\django\views\decorators\csrf.py in wrapped_view
resp = view_func(*args, **kwargs) ...
▶ Local vars
G:\Python27\lib\site-packages\django\views\decorators\csrf.py in wrapped_view
return view_func(*args, **kwargs) ...
▶ Local vars
G:\Python27\lib\site-packages\djangorestframework-0.3.2-py2.7.egg\djangorestframework\views.py in dispatch
response_obj = handler(request, *args, **kwargs) ...
▶ Local vars
G:\Django-1.3.7\depot\depotapp\views.py in get
return request.session["cart"].items ...
▶ Local vars
G:\Python27\lib\site-packages\django\contrib\sessions\backends\base.py in __getitem__
return self._session[key] ...
▶ Local vars