<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def head(self, url, *args, **kwargs):
 """Returns response to http HEAD on provided url """

        res = self._conn.head(url, headers=self._prepare_headers(**kwargs))
        if res.status_code == 200:
            return res
        return None