public static IReadOnlyCollection <Period> GetHistoryFromFile() { string filePath = @"D:\\InterviewTest\InterviewTest.DriverData\DataFiles\HistoryData.json"; IDataFileReader fileDataReader = new FileDataReader(); string historyData = fileDataReader.ReadFileData(filePath); IDataParser jsondataParser = new JsonDataParser(); return(jsondataParser.ParseData <IReadOnlyCollection <Period> >(historyData)); }