* `filter` is a reference to a function, that is called and passed a page,
and returns true if the page should be filtered out of the list.
* `sort` specifies a sort order for the list. See
* `filter` is a reference to a function, that is called and passed a page,
and returns true if the page should be filtered out of the list.
* `sort` specifies a sort order for the list. See