diff --git a/tests/Fixtures/TestBundle/Document/TypedScalarValueTrait.php b/tests/Fixtures/TestBundle/Document/TypedScalarValueTrait.php
index b16d3c2..2159260 100644
--- a/tests/Fixtures/TestBundle/Document/TypedScalarValueTrait.php
+++ b/tests/Fixtures/TestBundle/Document/TypedScalarValueTrait.php
@@ -14,12 +14,12 @@
 
 trait TypedScalarValueTrait
 {
-    public function normalize(NormalizerInterface $normalizer, string $format = null, array $context = []): array|string|int|float|bool
+    public function normalize(NormalizerInterface $normalizer, ?string $format = null, array $context = []): array|string|int|float|bool
     {
         return $this->value;
     }
 
-    public function denormalize(DenormalizerInterface $denormalizer, array|string|int|float|bool $data, string $format = null, array $context = []): void
+    public function denormalize(DenormalizerInterface $denormalizer, array|string|int|float|bool $data, ?string $format = null, array $context = []): void
     {
         $this->value = $data;
     }