private string GetDocumentSavingPath(HttpPostedFileBase file, int documentId)
        {
            if (file == null)
            {
                throw new ArgumentNullException(ErrorMessagesConstants.CannotSaveNullFile);
            }

            var savingDirName = documentId % 100;

            var filesHelper   = new FilesHelper();
            var fileExtension = filesHelper.GetFileExtension(file.FileName);
            var saveDirPath   = $"~/Files/Documents/{savingDirName}";

            if (!Directory.Exists(saveDirPath))
            {
                Directory.CreateDirectory(Server.MapPath(saveDirPath));
            }

            return($"{saveDirPath}/{documentId}{fileExtension}");
        }