diff --git a/src/Transformer/AbstractTransformer.php b/src/Transformer/AbstractTransformer.php
index ed0b753..56c8244 100644
--- a/src/Transformer/AbstractTransformer.php
+++ b/src/Transformer/AbstractTransformer.php
@@ -31,7 +31,7 @@ abstract public function convert(object $entity): array;
      * @param string $properyName the property of the object
      * @param [type] $value the value to convert
      */
-    abstract public function castValue(string $objectClass, string $properyName, $value): void;
+    abstract public function castValue(string $objectClass, string $properyName, $value);
 
     /**
      * map a type to a typesense type field.