private void DeleteFiles(IEnumerable <string> relativeFilePaths)
        {
            foreach (var relativeFilePath in relativeFilePaths)
            {
                string serverFilePath = _hostingEnvironment.GenerateServerFilePath(relativeFilePath);

                if (System.IO.File.Exists(serverFilePath))
                {
                    System.IO.File.Delete(serverFilePath);
                }
            }
        }