@Override
    public Optional<DuoSecurityAdminApiService> getAdminApiService() {
        if (StringUtils.isNotBlank(properties.getDuoAdminIntegrationKey()) && StringUtils.isNotBlank(properties.getDuoAdminSecretKey())) {
            return Optional.of(new DefaultDuoSecurityAdminApiService(this.httpClient, properties));
        }
        return Optional.empty();
    }
This is {@link BaseDuoSecurityAuthenticationService}.

@author Misagh Moayyed
@since 5.1.0
support/cas-server-support-duo-core/src/main/java/org/apereo/cas/adaptors/duo/authn/BaseDuoSecurityAuthenticationService.java