Should I add a trailing comma after the last argument in a function call?

Question

What is better to do?

self.call(1, True, \"hi\")

or

self.call(1, True, \"hi\",)

And what in the following

Answer 1

In data structures, the trailing comma is "useful" for making it easier to add items:

a = [
      1,
      2,
      3,
    ]

is easier to change into

a = [
      1,
      2,
      3,
      4,
      5,
    ]

because you don't have to edit the line that says 3,.

But there is no such benefit in function calls which usually don't change in length. So I would discourage the use of a trailing comma.