Fix bug

Author: olivervogel

src/Sign.php

@@ -154,10 +154,12 @@ public function localize(?string $locale = null): SignInterface
 
         $translatedName = $this->translator()->get($key, locale: $locale);
 
-        if (is_string($translatedName)) {
-            $this->name = $translatedName;
+        if (!is_string($translatedName)) {
+            throw new LocalizationException('No translation for "' . $key . '" in locale "' . $locale . '"');
         }
 
+        $this->name = $translatedName;
+
         return $this;
     }