Why Python built in “all” function returns True for empty iterables?

Question

I know it has a good reason, but I want to know what reason?

>>> print all([])
True

If all() is intended to check if every item on

Answer 1

Suppose all([]) is False.

Then, for all non empty list A, all(A + []) should be also False as

all(A + []) = all(A) and all([])
            = all(A) and False
            = False

Since A + [] = A, we know

all(A + []) = all(A) for any non empty list A

But, all(A) could be True (e.g., A = [True])

Hence,

for all non empty list A, all(A + []) should be also False

This contradicts. As a result, the first assumption is wrong and

all([]) is True