Code issues for help

[CurryQAQ]

Traceback (most recent call last):
File "D:\PycharmProjects\HighwayEnv-master\scripts\sb3_highway_ppo_transformer.py", line 406, in
env.viewer.set_agent_display(
AttributeError: 'NoneType' object has no attribute 'set_agent_display'

This script ran out of errors(sb3_highway_ppo_transformer),How can I solve this problem, please

[Peterzhoujr]

I found the same problem,do you get the answers now?

[CurryQAQ]

sorry,no