Merge branch '7.1' into 7.2

* 7.1:
  Updated the code example
  __isset() returns true only if values are present

Author: javiereguiluz

components/property_access.rst

@@ -252,7 +252,7 @@ The ``getValue()`` method can also use the magic ``__get()`` method::
 
         public function __isset($id): bool
         {
-            return true;
+            return isset($this->children[$id]);
         }
     }