If you don't want to add the MoreLinq library to the challenge just to get the DistinctBy functionality then you can get the same final result utilizing the overload of Linq's Unique strategy that can take within an IEqualityComparer argument. This is great, just isn't it: You can start with https://propertyingurugram.in/mvn-infrastructure-celebrates-mvn-malls-new-office-opening-with-traditional-hawan-ceremony/