diff --git a/src/ArraySimple.php b/src/ArraySimple.php
index dff741b..55f4b83 100644
--- a/src/ArraySimple.php
+++ b/src/ArraySimple.php
@@ -36,7 +36,7 @@ class ArraySimple
     protected static function extractKeys(string $simpleKey) : array
     {
         \preg_match_all('#\[(.*?)\]#', $simpleKey, $matches);
-        return $matches[1] ?? [];
+        return $matches[1];
     }
 
     /**