<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def write_raw(self, resp: Union[bytes, requests.Response], filename: str) -> None: """Write raw response data into a file. .. versionadded:: 4.2.1"""

        self.log(filename, end=' ', flush=True)
        with open(filename, 'wb') as file:
            if isinstance(resp, requests.Response):
                shutil.copyfileobj(resp.raw, file)
            else:
                file.write(resp)