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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _find_rule_no(self, mac):
 """Find rule number associated with a given mac."""


        ipt_cmd = ['iptables', '-L', '--line-numbers']
        cmdo = dsl.execute(ipt_cmd, self._root_helper, log_output=False)
        for o in cmdo.split('\n'):
            if mac in o.lower():
                rule_no = o.split()[0]
                LOG.info('Found rule %(rule)s for %(mac)s.',
                         {'rule': rule_no, 'mac': mac})
                return rule_no