private void AddRedColourSurcharge(Order order, int formatWidth)
{
_stringBuilder.AppendFormat($"{{0, {-formatWidth}}}", "Red colour surcharge");
var quantity = order.Blocks.Count(b => b.Colour == Colour.Red);
var price = ColourExtensions.GetPrice(Colour.Red);
var subtotal = quantity * price;
_stringBuilder.AppendLine($"{quantity} @ ${price} each = ${subtotal}");
}