How to filter expired content

Hi!

We are experiencing that expired content shows up in the search result. We tried applying filterforvisitor, like shown below, but it didn't work. How can we filter out the expired content?

var visitorFilter = _findClient.BuildFilter<PageData>().FilterForVisitor();
var result = query.Filter(visitorFilter).SortBy(request.SortBy)
                              .Skip(skip)
                              .Take(pageSize)
                              .ApplyBestBets()
                              .FuzzyMatch(request.Query, x => x.Heading)
                              .FuzzyMatch(request.Query, x => x.MainIntro)
                              .GetContentResult();