public static LabelSelectorBuilder<?> builder() {
        return new LabelSelectorBuilder<>();
    }
@Test
    void builderTest() {
        var labelSelector = LabelSelector.builder()
            .eq("a", "v1")
            .in("b", "v2", "v3")
            .build();
        assertThat(labelSelector.toString())
            .isEqualTo("a equal v1, b IN (v2, v3)");
    }