parenthesis around a tuple of literals in a for

[snippsat]

, outside of data structure like eg list it will always make a tuple.

>>> 1, 2
(1, 2)

>>> 'hello', 'world'
('hello', 'world')

So for x in 1,2,3: is just the same as for x in (1,2,3):

In a list is , parsed as separator,then 1, 2, 3 is three separate element and not a tuple.
For it to be a tuple or list inside a list comprehension then have to make it so () [].

>>> [x for x in (1,2,3)]
[1, 2, 3]

>>> [x for x in [1,2,3]]
[1, 2, 3]