python3: add list filter tag, useful to convert dictionary views

combo/public/templatetags/combo.py

@@ -220,3 +220,7 @@ def get_group(group_list, group_name):
 @register.filter(name='is_empty_placeholder')
 def is_empty_placeholder(page, placeholder_name):
     return len([x for x in page.get_cells() if x.placeholder == placeholder_name]) == 0
+
+@register.filter(name='list')
+def as_list(obj):
+    return list(obj)