public static <T> Optional<T> getFieldValue(final Object target, final String fieldName) {
        return findField(fieldName, target.getClass()).map(optional -> getFieldValue(target, optional));
    }
@Test
    void assertGetFieldValue() {
        assertThat(ReflectionUtils.getFieldValue(new ReflectionFixture(), "instanceValue").orElse(""), is("instance_value"));
        assertFalse(ReflectionUtils.getFieldValue(new ReflectionFixture(), "not_existed_field").isPresent());
    }