为什么我在浏览器输入了127.0.0.1:8000 之后，报了下面的错误，u'account' is not a registered namespace

[fdl66]

Request Method:	GET
http://127.0.0.1:8000/
1.9.6
NoReverseMatch
u'account' is not a registered namespace
/home/dl/code/xm/OJ_PY_ENV/lib/python2.7/site-packages/django/core/urlresolvers.py in reverse, line 596
/home/dl/code/xm/OJ_PY_ENV/bin/python
2.7.13
['/home/dl/code/py/test/test_niji', '/home/dl/code/xm/OJ_PY_ENV/lib/python27.zip', '/home/dl/code/xm/OJ_PY_ENV/lib64/python2.7', '/home/dl/code/xm/OJ_PY_ENV/lib64/python2.7/plat-linux2', '/home/dl/code/xm/OJ_PY_ENV/lib64/python2.7/lib-tk', '/home/dl/code/xm/OJ_PY_ENV/lib64/python2.7/lib-old', '/home/dl/code/xm/OJ_PY_ENV/lib64/python2.7/lib-dynload', '/usr/lib64/python2.7', '/usr/lib/python2.7', '/home/dl/code/xm/OJ_PY_ENV/lib/python2.7/site-packages', '/home/dl/code/py/test/test_niji']
Wed, 9 Aug 2017 05:17:22 +0000

[ericls]

请修改

NIJI_LOGIN_URL_NAME = "account:login"
NIJI_REG_URL_NAME = "account:reg"