D("foo.com","none",
    A("@","1.2.3.4", TTL("300s")),
    A("@","1.2.3.4", TTL("300")),
    A("@","1.2.3.4", TTL("3m")),
    A("@","1.2.3.4", TTL("3h")),
    A("@","1.2.3.4", TTL("3d"))
);