@Override
            public List<String> getSource() {
                return getMultifactorAuthenticationProviders()
                    .stream()
                    .filter(BeanSupplier::isNotProxy)
                    .sorted(OrderComparator.INSTANCE)
                    .map(MultifactorAuthenticationProvider::getDeviceManager)
                    .filter(Objects::nonNull)
                    .map(MultifactorAuthenticationDeviceManager::getSource)
                    .flatMap(List::stream)
                    .toList();
            }
This is {@link DefaultChainingMultifactorAuthenticationProvider}.

@author Misagh Moayyed
@since 6.1.0
core/cas-server-core-authentication-mfa-api/src/main/java/org/apereo/cas/authentication/DefaultChainingMultifactorAuthenticationProvider.java