fix for python2
fix for python2

jvgomez/ompl,jvgomez/ompl,jvgomez/ompl,jvgomez/ompl,utiasASRL/batch-informed-trees,jvgomez/ompl,utiasASRL/batch-informed-trees,utiasASRL/batch-informed-trees,utiasASRL/batch-informed-trees,jvgomez/ompl,utiasASRL/batch-informed-trees,utiasASRL/batch-informed-trees