trpo-gae-v0 and cem-v1 by @joschu
Any of available agents starts by checking if observation space is a Box, reference
CEM by @jietang
Same situation as trpo-gae-v0 and cem-v1, reference
DDPG by rmst It is clearly stated that only Box will be accepted reference
alg_4obdZl7SpmxIhYrjA4uA by @tambet
Expects observation space to contain shape
attribute which implies it must be a Box, reference