pango:attr-list-filter (attrlist func)

attrlist -- a pango:attr-list instance
func -- a pango:attr-filter-func callback function, returns true if an attribute should be filtered out

The new pango:attr-list instance or nil if no attributes of the given types were found.

Given a attribute list and callback function, removes any elements of the attribute list for which func returns true and inserts them into a new attribute list.