@PublicAPI(usage = ACCESS)
    public JavaPackage getPackage(String packageName) {
        return getValue(tryGetPackage(packageName), "This package does not contain any sub package '%s'", packageName);
    }
@Test
    public void function_GET_RELATIVE_NAME() {
        JavaPackage defaultPackage = importDefaultPackage(Object.class);

        String name = GET_RELATIVE_NAME.apply(defaultPackage.getPackage("java.lang"));

        assertThat(name).isEqualTo("lang");
    }