<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def address(self, num):
 """Search for company addresses by company number. Args: num (str):
 Company number to search on. """

        url_root = "company/{}/registered-office-address"
        baseuri = self._BASE_URI + url_root.format(num)
        res = self.session.get(baseuri)
        self.handle_http_error(res)
        return res