accessing agents type

[AliBehdar]

Hi
in humoristic test code code you have used
env.unwrapped infos, global_episode_return, episode_returns = heuristic_episode(env.unwrapped, args.render, seed+i)
then in heuristic_episode it do
agents = env.agents
agvs = [a for a in agents if a.type == AgentType.AGV]
pickers = [a for a in agents if a.type == AgentType.PICKER]
but when create en env and want to get agvs in the same it gives me :
{}