Edited urls.py

widget_CtrlF/announcement_board/urls.py

 from django.urls import path
 
-from .views import index
+from .views import (
+    index, 
+    AnnouncementsDetailView, 
+    AnnouncementsCreateView,
+    AnnouncementsUpdateView,
+)
 
 urlpatterns = [
     path('', index, name='index'),
+    path('<int:pk>/details/', AnnouncementsDetailView.as_view(), name='announcement-details'),
+    path('add/', AnnouncementsCreateView.as_view(), name='announcement-add'),
+    path('<int:pk>/edit/', AnnouncementsUpdateView.as_view(), name='announcement-edit'),
 ]
 
-app_name = 'announcement_board' 
+app_name = 'announcements' 
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