If An airline is "countable", this means that there MUST be a flight attendant present on the plane, whose sole job is to count: I noticed that if I use IEnumerable, when I debug and inspect "yığın", which in that case is the IEnumerable, it saf some interesting members: "inner", https://lanexkvfo.wikijm.com/782947/c_ienumerable_nerelerde_kullanılıyor_seçenekler