using stable baselines, why do you have to use a lambda function while wrapping an enviroment

Web: https://www.reddit.com/r/reinforcementlearning/comments/uo1fdm/using_stable_baselines_why_do_you_have_to_use_a/

I have been searching for an hour and can't find it. It seems so silly to me. I have accepted it but would really like to know what the logic behind it is.

example:

DummyVecEnv(\[lambda: env\])
this works

DummyVecEnv(\[env\])
this does not work

function lambda reinforcementlearning