public void AddAuthor(AuthorModel author)
{
_validator.ValidateAuthor(author);
var authorFilter = new AuthorFilterModel {
Name = author.Name
};
var dbAuthor = _authorRepository.Get(authorFilter).FirstOrDefault();
if (dbAuthor is not null)
{
throw new CustomApiException(HttpStatusCode.UnprocessableEntity, Constants.AUTHORALREADYEXISTSERROR);
}
dbAuthor = _mapper.Map <AuthorEntity>(author);
_authorRepository.Insert(dbAuthor);
}