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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 _update_port_group_info(self, switches=None):
 """Refresh data on switch interfaces' port group membership"""

        if switches is None:
            switches = self._switches.keys()
        for switch_ip in switches:
            client = self._switches.get(switch_ip)
            ret = self._run_eos_cmds(['show interfaces'], client)
            if not ret or len(ret) == 0:
                LOG.warning("Unable to retrieve interface info for %s",
                            switch_ip)
                continue
            intf_info = ret[0]
            self._port_group_info[switch_ip] = intf_info.get('interfaces', {})