class DefaultSmsSenderProvider implements SmsSenderProvider {

    @Override
    public Optional<SimpleSmsSender> lookupSimpleSmsMessageSenderFor(final String providerType) {
        assertValidProviderTypeArgument(providerType);
        return Optional.ofNullable(registeredSimpleSmsSenders.get(providerType));
    }

      DefaultSmsSenderProvider(final List<SimpleSmsSenderRegistry> simpleSmsSenderRegistries,
                             final List<TemplatedSmsSenderRegistry> templatedSmsSenderRegistries);

}