/// <summary>
 /// Simple search for Characteristic objects
 /// </summary>
 /// <param name="sign"><see cref="Util.GetList.Sign"/></param>
 /// <param name="options"><see cref="Util.GetList.Options"/></param>
 /// <param name="low">Lower value</param>
 /// <param name="high">Upper value or '_' for empty</param>
 /// <returns>List of Characteristics or <code>null</code> on error</returns>
 public CharacteristicGetListResponse GetList(GetList.Sign sign, GetList.Options options, string low, string high = "_")
 {
     var getList = new CharacteristicGetList
     {
         CharactRange = new[]
         {
             new Bapicharactrangetable
             {
                 Sign = Util.GetList.ToValue(sign),
                 Option = Util.GetList.ToValue(options),
                 Low = low,
                 High = high
             }
         }
     };
     
         return _sapCharacteristic.CharacteristicGetList(getList);
 }
        public ClassGetListResponse GetList(string classTypeNumber, GetList.Sign sign, GetList.Options options, string low, string high = "_")
        {
            var getList = new ClassGetList()
            {
                ClassSelection = new[]
                {
                    new Bapiclasssel()
                    {
                        Sign      = Util.GetList.ToValue(sign),
                        Option    = Util.GetList.ToValue(options),
                        ClassLow  = low,
                        ClassHigh = high
                    }
                },
                Classtype_Imp = classTypeNumber
            };

            return(_sapClass.ClassGetList(getList));
        }