addFilter
⚠️ Deprecated ⚠️
This is deprecated since version 4.10.
Use class@Gtk.FileDialog instead
---Adds @filter to the list of filters that the user can select between.
When a filter is selected, only files that are passed by that filter are displayed.
Note that the @chooser takes ownership of the filter if it is floating, so you have to ref and sink it if you want to keep a reference.
Parameters
filter
a GtkFileFilter