HarmonyOS TextPicker多列问题

参考如下示例：

@Entry
@Component
struct TextPickerExample {
  private cascade: string[] | TextCascadePickerRangeContent[] = [{
    text: '辽宁省',
    children: [{ text: '沈阳市', children: [{ text: '沈河区' }, { text: '和平区' }, { text: '浑南区' }] },
      { text: '大连市', children: [{ text: '中山区' }, { text: '金州区' }, { text: '长海县' }] }]
  }, {
    text: '吉林省',
    children: [{ text: '长春市', children: [{ text: '南关区' }, { text: '宽城区' }, { text: '朝阳区' }] },
      { text: '四平市', children: [{ text: '铁西区' }, { text: '铁东区' }, { text: '梨树县' }] }]
  }, {
    text: '黑龙江省',
    children: [{ text: '哈尔滨市', children: [{ text: '道里区' }, { text: '道外区' }, { text: '南岗区' }] },
      { text: '牡丹江市', children: [{ text: '东安区' }, { text: '西安区' }, { text: '爱民区' }] }]
  }]
  private select: number | number[] = []

  build() {
    Column() {
      TextPicker({ range: this.cascade, selected: $$this.select }).onChange((value: string | string[], index: number | number[]) => {
        console.info('TextPicker 多列联动：onChange ' + JSON.stringify(value) + ', ' + 'index: ' + JSON.stringify(index))
        console.info('TextPicker 多列联动：select ' + this.select)
      })
    }
  }
}