public async Task <ActionResult <AuthorApiViewModel> > Get(Guid id)
        {
            Author result = await _mediator.Send(new GetAuthorByIdQuery(id));

            if (result is null)
            {
                return(NotFound(id));
            }

            AuthorApiViewModel viewModel = AuthorApiMapper.MapToApiModel(result);

            SingleResult <AuthorApiViewModel> response =
                new SingleResult <AuthorApiViewModel>(viewModel);

            return(Ok(response));
        }