public IEnumerable<IStockRealTime> GetLatest(IEnumerable<string> stockCodes)
        {
            List<RealTimeItem> result = new List<RealTimeItem>();
            foreach(string code in stockCodes)
            {
                string filePath = string.Empty;
                if (PathHelper.GetLatestFilePath(code, ref filePath))
                {
                    var file = new RealTimeFile(filePath);
                    result.Add(file.Read(file.Header.DataCount - 1));
                }
            }

            return result.Cast<IStockRealTime>();
        }
        public IEnumerable<IStockRealTime> GetData(string stockCode, DateTime startDate, DateTime endDate)
        {
            List<string> pathList = PathHelper.GetFilePath(stockCode, startDate, endDate).ToList();

            List<RealTimeItem> result = new List<RealTimeItem>();
            foreach(string path in pathList)
            {
                if(File.Exists(path))
                {
                    var file = new RealTimeFile(path);
                    result.AddRange(file.ReadAll());
                }
            }

            return result.Cast<IStockRealTime>();
        }