1.py

from contextlib import contextmanager
from typing import Any


@contextmanager
def foo() -> Any:
    print("1 before")
    yield
    print("1 after")


class dual_foo:
    def __init__(self, *args, **kwargs):
        print("run")

    def __enter__(self, *args, **kwargs):
        ...

    def __exit__(self, exc_type, exc_val, exc_tb):
        print("cleanup")


if __name__ == "__main__":
    print("== context call:")
    with dual_foo():
        pass

    print("== standalone call:")
    dual_foo()

== context call:
run
cleanup
== standalone call:
run