private function getUserEntityClass()
    {
        /** @var ClassMetadata $meta */
        foreach ($this->getDoctrine()->getManager()->getMetadataFactory()->getAllMetadata() as $meta) {
            $reflectionClass = $meta->getReflectionClass();

            if (true === $this->hasAbstractParent($reflectionClass, User::class)) {
                return $meta->getName();
            }
        }

        return null;
    }