human
I wrote the below code

    def _OnFetch(response):
        if (response.code == 200):
            with open(output_file, 'w') as f:
                f.write(response.body)
                logging.info(('wrote    %d    bytes    to    %s' % (len(response.body), output_file)))
        else:
            logging.error(('failed    to    fetch    %s' % log_url))
        callback()
    http_client.fetch(log_url, callback=_OnFetch, method='GET')

What's a good function header?

=====
Here's a good function header?
assistant
#Here's a good function header.

def _FetchLog(http_client, log_url, output_file, callback):