Get BID side from DukasCopyHistorySource

var history = new DukasCopyHistorySource(new CsvNativeIdStorage("C:\test\asd.csv"), new InMemoryExchangeInfoProvider());

var security = new Security()
{
	Id = "EURUSD",
};

var timeFrame = TimeSpan.FromHours(1);

var timeFrameCandleMessages = history.LoadCandles(security, timeFrame, new DateTime(2019, 1, 1), Level1Fields.Yield);

This code only gets me ASK prices. I want to download only BID prices. How I can do this?