What is the script to load the envrionment usd file in Isaac sim?

The code for adding a rigid body to the stage is as follows.

assets_root_path = get_assets_root_path()
asset_path = assets_root_path + "/Isaac/Robots/Jetbot/jetbot.usd"
add_reference_to_stage(usd_path=asset_path, prim_path="/World/Fancy_Robot")
jetbot_robot = world.scene.add(Robot(prim_path="/World/Fancy_Robot", name="fancy_robot"))

But if usd file represents environment, how to load it as a script?

For example, If I want to load usd file of " Isaac/Environments/Simple_Room/simple_room.usd" with script, what is the script for it?

I found example code “load_stage.py”