private void HandleAddAdmin(ChatUser user, string[] parts) { if (parts.Length == 1) { throw new InvalidOperationException("Who do you want to make an admin?"); } string targetUserName = parts[1]; ChatUser targetUser = _repository.VerifyUser(targetUserName); _chatService.AddAdmin(user, targetUser); _notificationService.AddAdmin(targetUser); _repository.CommitChanges(); }