HarmonyOS 鸿蒙Next：Error: member not exist，photoAccessHelper.PhotoKeys.WIDTH不能用吗？

HarmonyOS 鸿蒙Next：Error: member not exist，photoAccessHelper.PhotoKeys.WIDTH不能用吗？

import { Double } from '../common/model/Double';
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { dataSharePredicates } from '@kit.ArkData';
import { Logger } from '@ohos.utils/Index';

export class ImageUtils {
  static getImageSize(uri: string, context: Context): Promise<Double<number, number>> {
    return new Promise<Double<number, number>>(async (resolve: Function, error: Function) => {
      try {
        let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
        let predicates: dataSharePredicates.DataSharePredicates = new dataSharePredicates.DataSharePredicates();
        predicates.equalTo(photoAccessHelper.PhotoKeys.URI, uri);
        let fetchOptions: photoAccessHelper.FetchOptions = {
          fetchColumns: [],
          predicates: predicates
        };
        let fetchResult: photoAccessHelper.FetchResult<photoAccessHelper.PhotoAsset> = await phAccessHelper.getAssets(fetchOptions);
        let photoAsset: photoAccessHelper.PhotoAsset = await fetchResult.getFirstObject();
        let double = new Double<number, number>()
        double.first = photoAsset.get(photoAccessHelper.PhotoKeys.WIDTH) as number
        double.second = photoAsset.get(photoAccessHelper.PhotoKeys.HEIGHT) as number
        resolve(double)
      } catch (e) {
        Logger.debug("tag", `${e}`)
        error()
      }
    })
  }
}

调用后提示：[nodict]Error: member not exist，photoAccessHelper.PhotoKeys.WIDTH不能用吗？