code: public function process(ContainerBuilder $container): void
      {
          if (!$container->has('contao.picker.builder')) {
              return;
          }
  
          $definition = $container->findDefinition('contao.picker.builder');
          $references = $this->findAndSortTaggedServices('contao.picker_provider', $container);
  
          foreach ($references as $reference) {
              $definition->addMethodCall('addProvider', [$reference]);
          }
      }
docs: {@inheritdoc}