public Task <SourceSubscription> DeleteSubscriptionByIdAsync(int subscriptionId)
 {
     return(TryCatch(async() =>
     {
         var storageSubscription = await _storageBroker.SelectSourceSubscriptionByIdAsync(subscriptionId);
         ValidateStorageSubscription(storageSubscription, subscriptionId);
         return await _storageBroker.DeleteSourceSubscriptionAsync(storageSubscription);
     }));
 }