def sys_up_time
      varbind = @varbind_list[0]
      if varbind && (varbind.name == SYS_UP_TIME_OID)
        return varbind.value
      else
        raise InvalidTrapVarbind, "Expected sysUpTime.0, found " + varbind.to_s
      end
    end
def sys_up_time
      varbind = @varbind_list[0]
      if varbind && (varbind.name == SYS_UP_TIME_OID)
        return varbind.value
      else
        raise InvalidTrapVarbind, "Expected sysUpTime.0, found " + varbind.to_s
      end
    end
Returns the value of the mandatory sysUpTime varbind for this trap.

 Throws InvalidTrapVarbind if the sysUpTime varbind is not present.