def METHOD_NAME(self, mode = "VOLT:DC"):
    vcf = mode.split(":")[0]
    if (vcf != "VOLT") and (vcf != "CURR") and (vcf != "FREQ"):
        print >> sys.stderr, "HP_34401A: Input error in set_measurement_mode()!"
        return -1
    if (vcf == "FREQ"):
        com_str = "CONF:FREQ"
        self._visainstrument.write(com_str)
        sleep(0.1)
        return self.get_measurement_mode()
    if len(mode.split(":")) < 2:
        print >> sys.stderr, "HP_34401A: Input error in set_measurement_mode()!"
        return -1
    ac_dc = mode.split(":")[1]
    if (ac_dc != "AC") and (ac_dc != "DC"):
        print >> sys.stderr, "HP_34401A: Input error in set_measurement_mode()!"
        return -1
    mode = "%s:%s" % (vcf, ac_dc)
    com_str = "CONF:%s" % mode
    self._visainstrument.write(com_str)
    sleep(0.1)
    return self.get_measurement_mode()