public async Task <CommentModel> AddCommentAsync(CommentModel model) { model = model ?? throw new ArgumentNullException(nameof(model)); try { Comment entity = await this.repo.AddArticleCommentAsync(model.ToEntity()).ConfigureAwait(false); if (entity == null) { return(null); } CommentModel updatedModel = new CommentModel(); updatedModel.ToModel(entity); return(updatedModel); } catch { throw; } }