public void Test__Get_Fail()
        {
            // Arrange
            var source = new EntityB {
                Name2 = "A"
            };

            var multiTypeItems = new MultiTypeBinderBuilder <Key>()
                                 .WithType <EntityA>(opt1 => opt1
                                                     .WithProperty(x => x.Name1, Key.Name)
                                                     .FinalizeType())
                                 .WithType <EntityB>(opt1 => opt1
                                                     .WithProperty(x => x.Name2, Key.Name)
                                                     .FinalizeType())
                                 .Build()
                                 .Map(new List <object> {
                source
            });

            // Act, Assert
            Assert.Throws <Exception>(() => multiTypeItems.First()[Key.RandomKey]);
        }