@Override
    public boolean isOn(String feature) {
        FeatureFlag flag = getFlag(feature);
        if (flag == null) {
            LOG.warn("Feature flag '{}' is not set. Fall back to default value 'false'", feature);
            return false;
        }
        return flag.isOn();
    }
@Test
    void testGetBoolFeatureFlagDefaultValue() throws IOException {
        FeatureFlags flags = empty();

        assertThat(flags.isOn("notExist")).isFalse();
    }