@PublicAPI(usage = ACCESS)
    public static Transformer matching(String packageIdentifier) {
        PackageMatchingSliceIdentifier sliceIdentifier = new PackageMatchingSliceIdentifier(packageIdentifier);
        String description = "slices matching " + sliceIdentifier.getDescription();
        return new Transformer(sliceIdentifier, description);
    }
@Test
    public void matches_slices() {
        JavaClasses classes = importClassesWithContext(Object.class, String.class, List.class, Set.class, Pattern.class);

        assertThat(Slices.matching("java.(*)..").transform(classes)).hasSize(2);
        assertThat(Slices.matching("(**)").transform(classes)).hasSize(3);
        assertThat(Slices.matching("java.(**)").transform(classes)).hasSize(3);
        assertThat(Slices.matching("java.(*).(*)").transform(classes)).hasSize(1);
    }