Are these runners?

runner.py

# Python 3
import collections
Write = collections.namedtuple("Write", ["written"])

def hello_world():
    yield Write("Hello, world!")
    yield Write("Hello, world!")
    return 1

def identity(gen):
    try:
        e = next(gen)
        raise ValueError("Fatal Exception")
    except StopIteration as r:
        return r.value

def run_write(fh, gen):
    try:
        e = next(gen)
        while True:
            if isinstance(e, Write):
                fh.write(e.written)
                e = next(gen)
            else:
                e = gen.send((yield e))
    except StopIteration as r:
        fh.close()
        return r.value

def run_accumulate_write(acc, gen):
    try:
        e = next(gen)
        while True:
            if isinstance(e, Write):
                acc += e.written
                e = next(gen)
            else:
                e = gen.send((yield e))
    except StopIteration as r:
        yield Write(acc)
        return r.value

print(identity(
    run_write(open("hello.txt", "w"), hello_world())))

# Check contents
with open("hello.txt", "r") as fh:
    print(fh.read())

print(
    identity(
        run_write(open("hello.txt", "w"),
            run_accumulate_write("", hello_world()))))

# Check contents
with open("hello.txt", "r") as fh:
    print(fh.read())