Comment by maratc

The trailing comma communicates an intent of possibly adding more things in the future. I actually use it quite a lot -- when I have that intent.

In the above example, if I think I have listed all of the `important_numbers`, there is a certain point of not having the trailing comma there.

Here's another terrible example from `black`:

From this:

    my_print(f"This string has two parameters, `a` which is equal to {a} and `b` which is equal to {b}", 
        a=1, b=2)

To this:

    my_print(
        f"This string has two parameters, `a` which is equal to {a} and `b` which is equal to {b}",
        a=1,
        b=2,
    )

The trailing comma it added makes no sense whatsoever because I can not have an intent of adding more things -- I've already exhausted the parameters in the string!

On the top of it, I don't quite get why I need to change the way I write in order to please the machine. Who should be serving whom?

Edit: changed "print" to "my_print" to not have to argue about named parameters of print ("sep", "file" etc.).

Edit 2: here's a variant that `black` has no issues with whatsoever. It does not suggest a trailing comma or any other change:

    my_print(f"This string has two params, `a` which is {a} and `b` which is {b}", a=1, b=2)

So an existence of a trailing comma is a product of string length?