public async Task <IActionResult> PatchBook(Guid id, [FromBody] List <PatchDto> patchDtos)
        {
            if (id == Guid.Empty)
            {
                return(BadRequest());
            }

            var book = _libraryRepository.GetBookForAuthor(id, id);

            await _libraryRepository.ApplyPatchAsync(book, patchDtos);

            return(NoContent());
        }