我怎样才能修复这个问题并使其不被弃用

import 'package:purchases_flutter/purchases_flutter.dart';
class PurchaseApi{
  static const _apiKey = '';
  static Future init() async{
    await Purchases.setDebugLogsEnabled(true);
    await Purchases.setup(_apiKey);
  }

  static Future<List<Offering>> fetchOffers() async {
   try{
    final offerings = await Purchases.getOfferings();
    final current = offerings.current;
    return current == null ? [] : [current];
  } on PlatformException catch (e) {
      return [];
    }
  }
}

我已经改变了第一次等待购买。setLogLevel（真为LogLevel）;但是当我改变设置的时候，我得到了一个错误。错误是方法'PurchasesConfiguration'没有为类型'Purchases'定义。我已经尝试导入'package：purchases_flutter/models/purchases_configuration. dart';