Challenge 1: Convert an FBV to a ListView — Possible Solution
====================================================================

# BEFORE — Course 1's function-based view

def book_list(request):
    books = Book.objects.all()
    return render(request, "catalog/book_list.html", {"books": books})

# AFTER — catalog/views.py

from django.views.generic import ListView
from .models import Book

class BookListView(ListView):
    model = Book
    template_name = "catalog/book_list.html"
    context_object_name = "books"
    paginate_by = 10

# catalog/urls.py

from django.urls import path
from . import views

urlpatterns = [
    path("", views.BookListView.as_view(), name="book-list"),
]

<!-- catalog/templates/catalog/book_list.html — updated to use pagination -->

<ul>
{% for book in books %}
  <li>{{ book.title }}</li>
{% endfor %}
</ul>

{% if is_paginated %}
  <div class="pagination">
    {% if page_obj.has_previous %}
      <a href="?page={{ page_obj.previous_page_number }}">Previous</a>
    {% endif %}
    <span>Page {{ page_obj.number }} of {{ page_obj.paginator.num_pages }}</span>
    {% if page_obj.has_next %}
      <a href="?page={{ page_obj.next_page_number }}">Next</a>
    {% endif %}
  </div>
{% endif %}

WHY THIS WORKS
--------------
- model = Book tells ListView what to query (Book.objects.all() by
  default, exactly matching the original FBV's query) — context_object_name
  = "books" ensures the template variable name stays "books", matching
  what the existing template already expects, rather than ListView's
  default name of "object_list".
- paginate_by = 10 is the entire pagination implementation — the
  original FBV would have needed a Paginator import, manual page-number
  handling from request.GET, and slicing the queryset by hand to achieve
  the same result; ListView does all of that internally.
- is_paginated, page_obj, and paginator are all automatically added to
  the template context by ListView whenever paginate_by is set — no
  changes needed in the view itself to make that pagination UI possible,
  only in the template that displays it.
- The urls.py entry changed from views.book_list (a plain function) to
  views.BookListView.as_view() (per Course 1's Views chapter, this
  .as_view() conversion step is required for any class-based view).