private static object VerifyCreatingProducer(Lazy <InstanceProducer> lazy)
 {
     try
     {
         // We only check if the instance producer can be created. We don't verify building of the
         // expression. That will be done up the call stack.
         return(lazy.Value);
     }
     catch (Exception ex)
     {
         throw new InvalidOperationException(StringResources.ConfigurationInvalidCreatingInstanceFailed(
                                                 typeof(TService), ex), ex);
     }
 }