@Override
    public void addMultifactorAuthenticationProviders(final Collection<MultifactorAuthenticationProvider> providers) {
        multifactorAuthenticationProviders.addAll(providers);
    }
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