<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 async def stdout(self) -> AsyncGenerator[str, None]: """Asynchronous generator for lines from subprocess stdout."""

        await self.wait_running()
        async for line in self._subprocess.stdout:  # type: ignore
            yield line