Doc- clarify return types as instance of original type

[Aniketsy]

fixes #10965

[Aniketsy]

test_answer

test_sample

test_sample.py

assert 2 == 3
def test_answer():
>       assert 1 + 1 == 3
E       assert 2 == 3

test_sample.py:2: AssertionError

@larsoner I noticed that this test seems to fail consistently across PRs, is this an intentionally failing test(e.g , to verify ci/pytest behavious) ?