Add argument exclusions

Author: hxtree

phpstan.neon

@@ -5,4 +5,7 @@ parameters:
   ignoreErrors:
     - message: '#Argument of an invalid type Ouxsoft\\PHPMarkup\\Contract\\ElementPoolInterface supplied for foreach, only iterables are supported#'
       path: src/Engine.php
-      count: 2
+      count: 2
+    - message: '#mixed#'
+      path: src/ArgumentArray.php
+      count: 2

src/ArgumentArray.php

@@ -43,11 +43,6 @@ class ArgumentArray implements
      */
     private $index = 0;
 
-    /**
-     * @var array keys contain a list of arrays stored
-     */
-    private $keys = [];
-
     /**
      * Set a value type to avoid Type Juggling issues and extend data types
      *