Why do Python function docs include the comma after the bracket for optional args?

Question

The format of the function signatures in the Python docs is a bit confusing. What is the significance in putting the comma after the open bracket, rather than before? What

Answer 1

The brackets mean that you can leave out the part between them. So if the docs would be written the way you suggest, it would imply that you can write RegexObject.match(string,,) by leaving everything in brackets. Or RegexObject.match(string,,endpos) by just leaving out the second one. But you can't. If you leave out endpos, you also have to leave out the comma before it. And if you leave out pos, you have to leave out the comma before it as well as endpos. So it's written in a way that makes that clear.