new_contents: from django.conf.urls import url
  from . import views
  
  urlpatterns = [
      url(r'^pool/(?P<pk>[0-9a-zA-Z\/]+)/$', views.UserRedirectView.as_view(), name='pool'),
      url(r'^pool/(?P<pk>[\d\w_]+)$', views.pool_fix, name='pool_fix'), #allow decimal and words only.
  ]
  
subject: Create urls.py