Raymond Hettinger added the comment:
What you're seeing is a feature of the grammar.
Function allow an optional trailing comma in the argument list:
>>> pow(2, 5)
32
>>> pow(2, 5,)
32
So, to create a tuple inside in an argument list, you need the extra layer of
parentheses.
New submission from umedoblock:
But I found a real bug to use a tuple with a comma.
Python3 recognized "abc", expression as tuple of one element.
But type() and len() recognize "abc", expression as "abc" string.
So now, I found a real bug.
I'll show you below sentences.
>>> "abc",
('abc',)
