public String asPairsWithComment(String comment) {
        return new PropertiesWriter(pairs).writeString(comment);
    }
@Test
    public void pairsWithComment() {
        assertThat(createTestKeyValues().asPairsWithComment("this is a comment"),
                is("# this is a comment\n" +
                        "first=1\n" +
                        "second=2\n" +
                        "third=3\n" +
                        "FOURTH=4\n"));
    }