yieldfromasync.py

async def yieldfromexample():
    RESULT = yield from EXPR

# Would become
async def yieldfromexample():
    _i = aiter(EXPR)
    try:
        _y = await anext(_i)
    except StopAsyncIteration as _e:
        _r = _e.value
    else:
        while 1:
            try:
                _s = yield _y
            except GeneratorExit as _e:
                try:
                    _m = _i.aclose
                except AttributeError:
                    pass
                else:
                    await _m()
                raise _e
            except BaseException as _e:
                _x = sys.exc_info()
                try:
                    _m = _i.athrow
                except AttributeError:
                    raise _e
                else:
                    try:
                        _y = await _m(*_x)
                    except StopAsyncIteration as _e:
                        _r = _e.value
                        break
            else:
                try:
                    if _s is None:
                        _y = await anext(_i)
                    else:
                        _y = await _i.asend(_s)
                except StopAsyncIteration as _e:
                    _r = _e.value
                    break
    RESULT = _r