Changing the name of an argument in the main function results in a "modified starter code" error.

[seanlip]

To reproduce: open any question and change the argname in the main function, then submit. You'll see a "you've deleted or modified the starter code" error:

This error should, ideally, not be treated as such. Although changing the function name should be treated as invalid, changing the argname is a perfectly fine thing to do.