def _set_ntp_servers_60(self, primary, secondary=None):
        """Set ntp servers on PAN-OS 6.0 and lower"""
        xpath60 = pandevice.XPATH_DEVICECONFIG_SYSTEM
        xpath60_pri = xpath60 + "/ntp-server-1"
        xpath60_sec = xpath60 + "/ntp-server-2"
        element60_pri = ""
        element60_sec = ""

        if primary:
            element60_pri += "<ntp-server-1>%s</ntp-server-1>" % (primary,)
        if secondary:
            element60_sec += "<ntp-server-2>%s</ntp-server-2>" % (secondary,)
        self.xapi.edit(xpath60_pri, element60_pri)
        self.xapi.edit(xpath60_sec, element60_sec)
dataset/ETHPy150Open PaloAltoNetworks/SplunkforPaloAltoNetworks/bin/lib/pandevice/pandevice/base.py/PanDevice._set_ntp_servers_60/original