Boy, having a postional-only parameter in that first position would have been handy when we created this API (as Matthias pointed out). :)

The 'exec' keyword-only parameter is obviously the safest option here.

Making the first parameter positional-only and then making the other parameters optional would lead to the most fluid API long-term as people I suspect would much rather just pass in an object than always specifying the keyword-only parameter every time going forward. I also doubt anyone is specifying etype by name.

So my vote is:

+1 to a positional-only first parameter
+0 to 'exc' keyword-only parameter