public Pet Create(Pet petToCreate) { List <Pet> updatedPetsList = ReadAll().List.ToList(); petToCreate.Id = FakeDB.GetNextPetId(); petToCreate.Owner = FakeDB.ReadOwnerData().FirstOrDefault(o => o.Id == petToCreate.Owner.Id); updatedPetsList.Add(petToCreate); FakeDB.UpdatePetData(updatedPetsList); return(petToCreate); }