public async Task <IActionResult> GetAuthorCollection(
[FromRoute]
[ModelBinder(BinderType = typeof(ArrayModelBinder))]
IEnumerable <Guid> authorIds)
{
if (authorIds == null)
{
return(BadRequest());
}
var authors = await _courseLibraryRepository.GetAuthorsWithIdsAsync(authorIds);
var authorsDto = _mapper.Map <IEnumerable <AuthorDto> >(authors);
return(Ok(authorsDto));
}