Fix python 3.4 problem
Fix python 3.4 problem

learningequality/kolibri,indirectlylit/kolibri,indirectlylit/kolibri,mrpau/kolibri,learningequality/kolibri,learningequality/kolibri,learningequality/kolibri,mrpau/kolibri,mrpau/kolibri,indirectlylit/kolibri,mrpau/kolibri,indirectlylit/kolibri