PhpParser\Node\Stmt\Property::isPrivate PHP Method

    public function isPrivate()
    {
        return (bool) ($this->flags & Class_::MODIFIER_PRIVATE);
    }

 private function enterProperty(Property $node)
 {
     if ($node->isPrivate()) {
         foreach ($node->props as $property) {
             $this->privateAttributes[$property->name] = $node;
         }
     }
 }