name 'url_for' is not defined code example

Example: url(r'^articles/', include('articles.urls')), NameError: name 'url' is not defined

from django.contrib import adminfrom django.urls import pathfrom django import urlsfrom django.conf.urls import urlfrom goods import views urlpatterns = [    url(r'^admin/', admin.site.urls),    url(r'^index/$', views.index)#Specify the view function]