edit-author html can be accessed correctly and updating and redirecting works as intended.

Deokhyun_Lee_reading/bookshelf/urls.py

 from django.urls import path
-from .views import HomeView, AuthorListView, AuthorDetailView, AuthorAddListView ,BookListView, BookDetailView, BookAddListView, BookEditView
+from .views import HomeView, AuthorListView, AuthorDetailView, AuthorAddListView, AuthorEditView ,BookListView, BookDetailView, BookAddListView, BookEditView
 
 urlpatterns = [
     # for Home (landing page)
@@ -8,7 +8,7 @@ urlpatterns = [
     path('authors/', AuthorListView.as_view(), name='authors'),
     path('authors/<int:pk>/details', AuthorDetailView.as_view(), name='author_detail'),
     path('authors/add', AuthorAddListView.as_view(), name="add_author" ),
-    
+    path('authors/<int:pk>/edit', AuthorEditView.as_view(), name='author_edit'),
     # for Books page
     path('books/', BookListView.as_view(), name='books'),
     path('books/<int:pk>/details', BookDetailView.as_view(), name='book_detail'),

Deokhyun_Lee_reading/bookshelf/views.py

@@ -66,9 +66,9 @@ class BookEditView(UpdateView):
         form = AddBookForm(request.POST)
         if form.is_valid():
             # onSave is called, the form will have essential data and this includes pk as well. 
-            new_book = form.save()
+            update_book = form.save()
             # pass the pk and redirect. 
-            return redirect('book_detail', pk = new_book.pk)
+            return redirect('book_detail', pk = update_book.pk)
         else:
             return render(request, 'book_details.html', {'form': form})
 
@@ -86,5 +86,20 @@ class AuthorAddListView(CreateView):
             new_author = form.save()
             # pass the pk and redirect. 
             return redirect('author_detail', pk = new_author.pk)
+        else:
+            return render(request, 'author_details.html', {'form': form})
+        
+class AuthorEditView(UpdateView):
+    model = Author
+    form_class = AddAuthorForm
+    template_name = 'authors/edit-author.html'
+
+    def post(self, request, pk):
+        form = AddAuthorForm(request.POST)
+        if form.is_valid():
+            # onSave is called, the form will have essential data and this includes pk as well. 
+            update_author = form.save()
+            # pass the pk and redirect. 
+            return redirect('author_detail', pk = update_author.pk)
         else:
             return render(request, 'author_details.html', {'form': form})
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