Reliably get page children for list pages

hooks/nav.py

@@ -4,5 +4,11 @@ def is_list_page(page) -> bool:
 
     return page.parent.children[0] == page
 
+def children(page):
+    if not is_list_page(page):
+        return []
+    return page.parent.children[1:]
+
 def on_env(env, config, files):
     env.filters["is_list_page"] = is_list_page
+    env.filters["children"] = children

theme/main.html

@@ -7,4 +7,4 @@ Section: {{ page.is_section }}
 
 Is lits page: {{ page|is_list_page }}
 
-Children: {{ page.children }}
+Children: {{ page|children }}