public (bool ValidationResult, string ValidationMessage) ValidateGetNewChatMessages(Guid chatUid, Guid?messageUid) { if (!_chatRepository.CheckChatExistence(chatUid).Result) { return(false, ErrorDictionary.GetErrorMessage(19, _culture)); } if (messageUid.HasValue && !_chatRepository.CheckChatMessageExistence(messageUid.Value).Result) { return(false, ErrorDictionary.GetErrorMessage(11, _culture)); } return(true, string.Empty); }