1namespace domain
 2{
 3  using System.Collections.Generic;
 4
 5  public static class Summation
 6  {
 7    static public IQuantity Sum<T>(this IEnumerable<IQuantity> items) where T: IUnitOfMeasure,new()
 8    {
 9      var result = 0m.ToQuantity<T>();
10      foreach (var item in items) {
11        result = result.Plus(item);
12      }
13      return result;
14    }
15  }
16}