This is a Django mixin that allows ModelAdmin classes to execute actions without selecting any objects on the change list of the Django Admin.
To implement it you need to include the Mixin as usual (see https://docs.djangoproject.com/en/1.10/topics/class-based-views/mixins/)
and define a class attribute called extended_actions containing a list of string with the name of the actions that you want to be exectued
with empty queryset.
If in the action you want to use the same queryset that the user is seeing, you can use the get_filtered_queryset method also provided by the mixin