The best option is to use the Django built-in methods:
# Union methodresult_list = page_list.union(article_list, post_list)
That will return the union of all the objects in those querysets.
If you want to get just the objects that are in the three querysets, you will love the built-in method of querysets, intersection
.
# intersection methodresult_list = page_list.intersection(article_list, post_list)