But that's not a valid loader.

I'm still struggling here. I see what you're trying to get at, but I
can't see how I can write a valid loader that does this.

To test the problem you're suggesting (that the code calls load_module
when the module is already loaded) I need a valid loader which does
something detectably different of the module is already loaded when it runs.

Obviously, I can fix the get_data code - that's not even remotely hard.
But I'd rather create a failing test with the current code, so that I
can confirm that the "problem" is fixed. At the moment, I can't even
demonstrate a problem!