>>> def g():
...     print(1)
...     yield 1
...     print(2)
...     yield 2
...     print(3)
...     yield 3
...
>>> 2 in g()
1
2
True

In [1]: %timeit 10**20 in range(10**30)
375 ns ± 10.7 ns per loop

In : [(x, y) for x in range(3) for y in range(3)]
Out: [
    (0, 0), (0, 1), (0, 2),
    (1, 0), (1, 1), (1, 2),
    (2, 0), (2, 1), (2, 2)
]

In : [
    (x, y)
    for x in range(3)
    for y in range(3)
    if x != 0
    if y != 0
]
Out: [(1, 1), (1, 2), (2, 1), (2, 2)]

In : [
    (x, y)
    for x in range(3)
    for y in range(x + 2)
    if x != y
]
Out: [
    (0, 1),
    (1, 0), (1, 2),
    (2, 0), (2, 1), (2, 3)
]

In : [
    (x, y)
    for x in range(5)
    if x % 2
    for y in range(x + 2)
    if x != y
]
Out: [
    (1, 0), (1, 2),
    (3, 0), (3, 1), (3, 2), (3, 4)
]

def print_whole_file(
    *,
    path: Optional[str] = None,
    file_obj: Optional[TextIO] = None
):
    assert path or file_obj

    if path:
        with open(path) as f:
            print(f.read(), end='')
    else:
        print(file_obj.read(), end='')

def print_whole_file(
    *,
    path: Optional[str] = None,
    file_obj: Optional[TextIO] = None
):
    assert path or file_obj

    with ExitStack() as stack:
        if path:
            file_obj = stack.enter_context(
                open(path)
            )

        print(file_obj.read(), end='')

def print_whole_file(
    *,
    path: Optional[str] = None,
    file_obj: Optional[TextIO] = None
):
    assert path or file_obj

    if path:
        context = open(path)
    else:
        context = nullcontext(file_obj)

    with context as f:
        print(f.read(), end='')