function render(), ValueError: 'torso_1' is not in list

[Oanakiaja]

when I use learner_env.render() in main function to see the visualized result, it will get this bug.

ValueError: 'torso_1' is not in list .

I think it may lack of something in the _get_viewer() function.

[Mayankm96]

Do you have the correct gym and mujoco-py version installed? I had the same issue but it got fixed when I installed gym==0.7.4 and mujoco-py==0.5.7.