-        with transaction.atomic():
-            cursor = connection.cursor()
-            if connection.vendor == 'postgres':
-                cursor.execute("TRUNCATE catalogue_book_ancestor")
-                cursor.execute("""
-                    WITH RECURSIVE ancestry AS (
-                        SELECT book.id, book.parent_id
-                        FROM catalogue_book AS book
-                        WHERE book.parent_id IS NOT NULL
-                        UNION
-                        SELECT ancestor.id, book.parent_id
-                        FROM ancestry AS ancestor, catalogue_book AS book
-                        WHERE ancestor.parent_id = book.id
-                            AND book.parent_id IS NOT NULL
-                        )
-                    INSERT INTO catalogue_book_ancestor
-                        (from_book_id, to_book_id)
-                        SELECT id, parent_id
-                        FROM ancestry
-                        ORDER BY id;
-                    """)
-            else:
-                cursor.execute("DELETE FROM catalogue_book_ancestor")
-                for b in cls.objects.exclude(parent=None):
-                    parent = b.parent
-                    while parent is not None:
-                        b.ancestor.add(parent)
-                        parent = parent.parent
+        cursor = connection.cursor()
+        if connection.vendor == 'postgres':
+            cursor.execute("TRUNCATE catalogue_book_ancestor")
+            cursor.execute("""
+                WITH RECURSIVE ancestry AS (
+                    SELECT book.id, book.parent_id
+                    FROM catalogue_book AS book
+                    WHERE book.parent_id IS NOT NULL
+                    UNION
+                    SELECT ancestor.id, book.parent_id
+                    FROM ancestry AS ancestor, catalogue_book AS book
+                    WHERE ancestor.parent_id = book.id
+                        AND book.parent_id IS NOT NULL
+                    )
+                INSERT INTO catalogue_book_ancestor
+                    (from_book_id, to_book_id)
+                    SELECT id, parent_id
+                    FROM ancestry
+                    ORDER BY id;
+                """)
+        else:
+            cursor.execute("DELETE FROM catalogue_book_ancestor")
+            for b in cls.objects.exclude(parent=None):
+                parent = b.parent
+                while parent is not None:
+                    b.ancestor.add(parent)
+                    parent = parent.parent