public static OrderQuantity GetOrderQuantity(
this IOrder order)
{
var notNullOrder = order.EnsureNotNull(nameof(order));
return(notNullOrder.Quantity.HasValue
? OrderQuantity.Fractional(notNullOrder.Quantity.Value)
: notNullOrder.Notional.HasValue
? OrderQuantity.Notional(notNullOrder.Notional.Value)
: throw new InvalidOperationException());
}
