import types
import itertools

@types.coroutine
def _async_yield(v):
    return (yield v)

class MyExc(Exception):
    pass

async def agenfn():
    for i in itertools.count():
        try:
            await _async_yield(i)
        except MyExc:
            pass
    return
    yield


agen = agenfn()
gen = agen.asend(None)
print(f"{gen.send(None)}")
gen2 = agen.asend(None)
try:
    print(f"{gen2.throw(MyExc)}")
except RuntimeError:
    print("good")
else:
    print("bad")

gen3 = agen.athrow(MyExc)
try:
    print(f"{gen3.throw(MyExc)}")
except RuntimeError:
    print("good")
else:
    print("bad")