bugfix in python 3
bugfix in python 3

MarkAWard/optunity,claesenm/optunity,MarkAWard/optunity,chrinide/optunity,MarkAWard/optunity,claesenm/optunity,chrinide/optunity,chrinide/optunity,chrinide/optunity,claesenm/optunity,MarkAWard/optunity,claesenm/optunity