### Question:
Labels extends ImmutableKeyValuePairs<String, String> { public static Labels of(String key, String value) { return sortAndFilterToLabels(key, value); }  abstract void forEach(LabelConsumer consumer); static Labels empty(); static Labels of(String key, String value); static Labels of(String key1, String value1, String key2, String value2); static Labels of(
      String key1, String value1, String key2, String value2, String key3, String value3); static Labels of(
      String key1,
      String value1,
      String key2,
      String value2,
      String key3,
      String value3,
      String key4,
      String value4); static Labels of(
      String key1,
      String value1,
      String key2,
      String value2,
      String key3,
      String value3,
      String key4,
      String value4,
      String key5,
      String value5); static Labels of(String[] keyValueLabelPairs); Builder toBuilder(); static Builder newBuilder();  }### Answer:
@Test void orderIndependentEquality() { Labels one = Labels.of( "key3", "value3", "key1", "value1", "key2", "value2"); Labels two = Labels.of( "key2", "value2", "key3", "value3", "key1", "value1"); assertThat(one).isEqualTo(two); }
@Test void deduplication() { Labels one = Labels.of( "key1", "valueX", "key1", "value1"); Labels two = Labels.of("key1", "value1"); assertThat(one).isEqualTo(two); }
@Test void threeLabels() { Labels one = Labels.of( "key1", "value1", "key3", "value3", "key2", "value2"); assertThat(one).isNotNull(); }
@Test void fourLabels() { Labels one = Labels.of( "key1", "value1", "key2", "value2", "key3", "value3", "key4", "value4"); assertThat(one).isNotNull(); }