public static IFunctor <B> fmap <A, B>(this Func <A, B> f, IFunctor <A> a) => a.fmap(f);
// ----
private static IFunctor <string> DoFmap(IFunctor <int> v)
{
return(v.fmap(x => x * 2).fmap(x => "Value is '" + x + "'"));
}
