diff --git a/src/ClassUtils.php b/src/ClassUtils.php
index 92941bf..5d70c22 100644
--- a/src/ClassUtils.php
+++ b/src/ClassUtils.php
@@ -34,7 +34,9 @@ public static function shortenClassFromCode($code, callable $callback = null)
                 return static::shortenClassName($matches[1]);
             };
         }
-
+        if(is_null($code)) {
+            return "";
+        }
         $codeParsed = \preg_replace_callback('@((?:\\\\{1,2}\w+|\w+\\\\{1,2})(?:\w+\\\\{0,2})+)@', $callback, $code);
 
         return $codeParsed;