public Labels withAdditionalLabels(Map<String, String> additionalLabels) {
        if (additionalLabels == null || additionalLabels.isEmpty()) {
            return this;
        } else {
            Map<String, String> newLabels = new HashMap<>(labels.size());
            newLabels.putAll(labels);
            newLabels.putAll(Labels.additionalLabels(additionalLabels).toMap());

            return new Labels(newLabels);
        }
    }
@Test
    public void testParseNullLabelsInUserLabels()   {
        assertThat(Labels.EMPTY.withAdditionalLabels(null), is(Labels.EMPTY));
    }