Builder<Integer, String> builder =
        new Builder<Integer, String>()
            .put(1, "un")
            .put(2, "deux")
            .put(70, "soixante-dix")
            .put(70, "septante")
            .put(70, "seventy")
            .put(1, "one")
            .put(2, "two");
    ImmutableMap<Integer, String> map = builder.buildKeepingLast();
    assertMapEquals(map, 1, "one", 2, "two", 70, "seventy");