private function getPropertyManipulator(EntityManagerInterface $entityManager): PropertyManipulator
    {
        $oid = spl_object_hash($entityManager);
        if (!isset($this->propertyManipulators[$oid])) {
            $this->propertyManipulators[$oid] = new PropertyManipulator();
        }

        return $this->propertyManipulators[$oid];
    }