Don't accept IEnumerable

VehicleProcessors.cs

public class Vehicle
{
    public required string Make { get; init; }
    public required string Model { get; init; }
    public required int Year { get; init; }
    public required decimal Price { get; init; }
}

public class BadVehicleProcessor
{
    private IEnumerable<Vehicle> vehicles;

    public BadVehicleProcessor(IEnumerable<Vehicle> vehicles)
    {
        this.vehicles = vehicles;
    }

    public Vehicle? GetOldestVehicle()
    {
        return this.vehicles.OrderBy(v => v.Year).FirstOrDefault();
    }

    public Vehicle? GetMostExpensiveVehicle()
    {
        return this.vehicles.OrderByDescending(v => v.Price).FirstOrDefault();
    }
}

public class GoodVehicleProcessor
{
    private IReadOnlyCollection<Vehicle> vehicles;

    public BadVehicleProcessor(IReadOnlyCollection<Vehicle> vehicles)
    {
        this.vehicles = vehicles;
    }

    // Identical implementation to BadVehicleProcessor
}