get router locator unicast IPv6 address

def getRloc(self):
        """get router locator unicast IPv6 address"""
        print '%s call getRloc' % self.port
        prefix = self.__stripValue(self.__sendCommand(WPANCTL_CMD + 'getprop -v IPv6:MeshLocalPrefix')[0])
        mlprefix = prefix.split('/')[0]
        rloc16 = self.__sendCommand(WPANCTL_CMD + 'getprop -v Thread:RLOC16')[0].lstrip('0x')
        print "prefix: " + prefix
        print "mlprefix: " + mlprefix
        print "rloc16: " + rloc16

        rloc = self.__padIp6Addr(mlprefix + '00ff:fe00:' + rloc16)
        print "rloc: " + rloc
        return rloc