public static <K, V> Map<K, V> emptyOnNull(Map<K, V> map) {
        return map == null ? new HashMap<>() : map;
    }
@Test
    void emptyOnNull() {
        var map = MapUtils.emptyOnNull(null);
        assertThat(map, notNullValue());
        assertThat(map, anEmptyMap());

        map = MapUtils.emptyOnNull(Map.of("key", "value"));
        assertThat(map, notNullValue());
        assertThat(map.size(), is(1));
    }