[rllib] Hierarchical Reinforcement Learning (HRL) implementation?

Hello,

I don’t see any signs of Hierarchical Reinforcement Learning (HRL) being implemented in RLlib (or anything similar to HRL). Is this accurate?
It seems like a useful method for solving complex environments, so I was wondering if there is interest in implementing it? There is a tensorflow 1.x implementation here, which may provide a good starting point: https://github.com/tensorflow/models/tree/master/research/efficient-hrl
The original paper can be found here: https://arxiv.org/abs/1805.08296