Depends on how it's set up. If the setting is going into the env it's a string, so I'd expect some sort of

if os.getenv("this_variable", "false").lower() == "true":   # or maybe "in true, yes, on, 1" if you want to be weird like yaml
  this_variable = True
else:
  this_variable = False

Except maybe a little more elegant and not typed on my phone.

But if the instructions are telling the user to edit the settings directly, like where I wrote this_variable=True, they'd need to case it correctly there.