finishTransaction returning undefined

[iamrohitagg]

I am calling finishTransaction after purchasing subscription like this

requestSubscription({
          sku: productIds,
          andDangerouslyFinishTransactionAutomaticallyIOS: false,
          ...(subscriptionOffers && {
            subscriptionOffers: [
              {sku: productIds, offerToken: subscriptionOffers},
            ],
          }),
        })
          .then(async res => {
            console.log(res);
            await finishTransaction({purchase: res, isConsumable: false}).then(
              res => {
                console.log(res);
              },
            );

But I am getting undefined in finish transaction response.And I am using the latest version of the library.