Fix jax-py3.7 incompatibility (#145)
Fix jax-py3.7 incompatibility (#145)

(cherry picked from commit 635feb97e786700a2a63e580a25daca239e5079b)
humancompatibleai/imitation,HumanCompatibleAI/imitation,humancompatibleai/imitation,HumanCompatibleAI/imitation