Server validation errors in .NET Core with FluentValidation via ExMethod

ControllerExtensions.cs

public static class ControllerExtensions
{
  public static void GetErrors(this Controller controller, object model, OperationResult result)
  {
    if (model == null)
    {
      result.Errors.Add("Ошибка ввода данных");
    }
    result.Errors.AddRange(controller.ModelState.Values.SelectMany(v => v.Errors
      .Where(b => !string.IsNullOrEmpty(b.ErrorMessage))
      .Select(b => b.ErrorMessage)));
  }
}

We provide result as parameter because in my buissness logic we also do some checks before and after validation.
But in other cases I'd love to return a new instance of OperationResult.