@contextmanager
def needRun():
    try:
        yield
    except RuntimeError as e:
        if e.args[0] != "generator didn't yield":
            raise  # Raising everything else


@contextmanager
def contextOnCondition(flag: bool=True):
    if flag:
        yield True


if __name__ == "__main__":
    flag = True
    with needRun(), contextOnCondition(flag):
        print("It ran")

    flag = False
    with needRun(), contextOnCondition(flag):
        print("It did not run")
Б>