internal static void Bennies(this ICollectionBe <Person> be)
 {
     be.Compose(persons =>
     {
         persons.ForEach(p =>
         {
             Expect(p).To.Be.A.Benny();
         });
     }, (collection, passed) =>
                $"Expected {MessageHelpers.Stringify(collection)} {passed.AsNot()}to all be Bennies");
 }