Better handling of optional arguments for later Django versions.
Better handling of optional arguments for later Django versions.

mrpau/kolibri,jonboiser/kolibri,indirectlylit/kolibri,DXCanas/kolibri,learningequality/kolibri,learningequality/kolibri,lyw07/kolibri,mrpau/kolibri,DXCanas/kolibri,mrpau/kolibri,christianmemije/kolibri,christianmemije/kolibri,indirectlylit/kolibri,mrpau/kolibri,lyw07/kolibri,lyw07/kolibri,jonboiser/kolibri,indirectlylit/kolibri,jonboiser/kolibri,benjaoming/kolibri,lyw07/kolibri,jonboiser/kolibri,indirectlylit/kolibri,learningequality/kolibri,DXCanas/kolibri,DXCanas/kolibri,christianmemije/kolibri,learningequality/kolibri,benjaoming/kolibri,benjaoming/kolibri,christianmemije/kolibri,benjaoming/kolibri