new appraoch

pancake/system/vendor/stripe/stripe-php/lib/Util/Set.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace Stripe\Util;
+
+use ArrayIterator;
+use IteratorAggregate;
+
+class Set implements IteratorAggregate
+{
+    private $_elts;
+
+    public function __construct($members = [])
+    {
+        $this->_elts = [];
+        foreach ($members as $item) {
+            $this->_elts[$item] = true;
+        }
+    }
+
+    public function includes($elt)
+    {
+        return isset($this->_elts[$elt]);
+    }
+
+    public function add($elt)
+    {
+        $this->_elts[$elt] = true;
+    }
+
+    public function discard($elt)
+    {
+        unset($this->_elts[$elt]);
+    }
+
+    public function toArray()
+    {
+        return \array_keys($this->_elts);
+    }
+
+    /**
+     * @return ArrayIterator
+     */
+    #[\ReturnTypeWillChange]
+    public function getIterator()
+    {
+        return new ArrayIterator($this->toArray());
+    }
+}