public JmxCollector register() {
        return register(PrometheusRegistry.defaultRegistry);
    }
@Test
    public void testValueIgnoreNonNumber() throws Exception {
        JmxCollector jc =
                new JmxCollector(
                                "\n---\nrules:\n- pattern: `.*`\n  name: foo\n  value: a"
                                        .replace('`', '"'))
                        .register(prometheusRegistry);
        assertNull(getSampleValue("foo", new String[] {}, new String[] {}));
    }