Search not working with Arabic language about searchable_dropdown HOT 3 CLOSED

class ExampleNumber {
  int number;

  static final Map<int, String> map = {
    0: "صفر",
    1: "واحد",
    2: "اثنان",
    3: "ثلاثة",
    4: "أربعة",
    5: "خمسة",
    6: "ستة",
    7: "سبعة",
    8: "ثمانية",
    9: "تسعة",
    10: "عشرة",
    11: "أحد عشر",
    12: "اثني عشر",
    13: "ثلاثة عشر",
    14: "أربعة عشر",
    15: "خمسة عشر",
  };

  String get numberString {
    return (map.containsKey(number) ? map[number] : "unknown");
  }

  ExampleNumber(this.number);

  String toString() {
    return ("$number $numberString");
  }

  static List<ExampleNumber> get list {
    return (map.keys.map((num) {
      return (ExampleNumber(num));
    })).toList();
  }
}
...
SearchChoices.single(
        items: ExampleNumber.list.map((exNum) {
          return (DropdownMenuItem(
              child: Text(exNum.numberString), value: exNum));
        }).toList(),
        value: selectedNumber,
        hint: "Select one number",
        searchHint: "Select one number",
        onChanged: (value) {
          setState(() {
            selectedNumber = value;
          });
        },
        dialogBox: true,
        isExpanded: true,
      )