diff --git a/Classes/Property/TypeConverter/Double2Converter.php b/Classes/Property/TypeConverter/Double2Converter.php
index 06ad658..30fe00b 100644
--- a/Classes/Property/TypeConverter/Double2Converter.php
+++ b/Classes/Property/TypeConverter/Double2Converter.php
@@ -41,7 +41,7 @@ class Double2Converter extends AbstractTypeConverter
      * @return bool
      * @internal only to be used within Extbase, not part of TYPO3 Core API.
      */
-    public function canConvertFrom($source, $targetType)
+    public function canConvertFrom($source, $targetType): bool
     {
         return is_string($source) ||is_integer($source);
     }