public Collection<String> getAllMetricNames() {
        Set<String> names = new HashSet<>();
        for (Identifier id : values.keySet()) {
            names.add(id.getName());
        }
        return names;
    }
@Test
    final void testGetAllMetricNames() {
        twoMetricsUniqueDimensions();
        Collection<String> names = bucket.getAllMetricNames();
        assertEquals(2, names.size());
        assertTrue(names.contains("nalle"));
        assertTrue(names.contains("nalle2"));
    }