public void And()
{
Option <int> opt1 = new Some <int>(1);
Assert.Equal(2, opt1.And(new Some <int>(2)).Unwrap());
Assert.Equal(None <int> .Instance, opt1.And(None <int> .Instance));
Option <int> opt2 = None <int> .Instance;
Assert.Equal(None <int> .Instance, opt2.And(new Some <int>(2)));
Assert.Equal(None <int> .Instance, opt2.And(None <int> .Instance));
}
