Sylius\Bundle\ThemeBundle\DependencyInjection\SyliusThemeExtension::addConfigurationSourceFactory PHP Method

    public function addConfigurationSourceFactory(ConfigurationSourceFactoryInterface $configurationSourceFactory)
    {
        $this->configurationSourceFactories[$configurationSourceFactory->getName()] = $configurationSourceFactory;
    }

 /**
  * {@inheritdoc}
  */
 protected function getContainerExtensions()
 {
     $themeExtension = new SyliusThemeExtension();
     $themeExtension->addConfigurationSourceFactory(new FilesystemConfigurationSourceFactory());
     return [$themeExtension];
 }