public function registerParameters(ContainerBuilder $container, array $config)
{
$container->setParameter('sonata.invoice.invoice.class', $config['class']['invoice']);
$container->setParameter('sonata.invoice.invoice_element.class', $config['class']['invoice_element']);
$container->setParameter('sonata.invoice.admin.invoice.entity', $config['class']['invoice']);
$container->setParameter('sonata.invoice.admin.invoice_element.entity', $config['class']['invoice_element']);
}