我收到以下错误类型“String”不是类型“List？”的子类型'将Map转换为BarModel对象时
尽管从响应中接收到int的列表，但仍抛出类型“String”不是类型“List”的子类型。将其分配给openDays时

List<int>? openDays;

BarModel.fromMap(Map<String, dynamic> json) {
    print(json['open_days']); // [1, 2, 3]
    barId = json['bar_id'];
    barName = json['bar_name'];
    barAddress = json['bar_address'];
    openDays = json['open_days']; // error type 'String' is not a subtype of type 'List<int>?'
  }