diff --git a/lib/StripeObject.php b/lib/StripeObject.php
index 8e9eb93c1..bc5d3981b 100644
--- a/lib/StripeObject.php
+++ b/lib/StripeObject.php
@@ -194,24 +194,37 @@ public function __debugInfo()
     }
 
     // ArrayAccess methods
+
+    /**
+     * @return void
+     */
     #[\ReturnTypeWillChange]
     public function offsetSet($k, $v)
     {
         $this->{$k} = $v;
     }
 
+    /**
+     * @return bool
+     */
     #[\ReturnTypeWillChange]
     public function offsetExists($k)
     {
         return \array_key_exists($k, $this->_values);
     }
 
+    /**
+     * @return void
+     */
     #[\ReturnTypeWillChange]
     public function offsetUnset($k)
     {
         unset($this->{$k});
     }
 
+    /**
+     * @return mixed
+     */
     #[\ReturnTypeWillChange]
     public function offsetGet($k)
     {