+ /**
+ * Get the Page that is used as default template for newly created pages within this Book.
+ */
+ public function defaultTemplate(): BelongsTo
+ {
+ return $this->belongsTo(Page::class, 'default_template_id');
+ }
+
+ /**
+ * Get the sort set assigned to this book, if existing.
+ */
+ public function sortRule(): BelongsTo
+ {
+ return $this->belongsTo(SortRule::class);
+ }
+