diff --git a/src/KdybyDateTimeProviderBundle.php b/src/KdybyDateTimeProviderBundle.php
index fd06bad..5c90c75 100644
--- a/src/KdybyDateTimeProviderBundle.php
+++ b/src/KdybyDateTimeProviderBundle.php
@@ -12,9 +12,20 @@
 
 namespace Kdyby\DateTimeProviderBundle;
 
+use Symfony\Component\DependencyInjection\Extension\ExtensionInterface;
+
 class KdybyDateTimeProviderBundle extends \Symfony\Component\HttpKernel\Bundle\Bundle
 {
 
 	use \Kdyby\StrictObjects\Scream;
 
+	public function getContainerExtension(): ExtensionInterface
+	{
+		if ($this->extension === NULL) {
+			$this->extension = $this->createContainerExtension();
+		}
+
+		return $this->extension;
+	}
+
 }