public function getRepository($entityName)
    {
        $entityName = ltrim($entityName, '\\');
        if (isset($this->repositories[$entityName])) {
            return $this->repositories[$entityName];
        }

        $metadata = $this->getClassMetadata($entityName);
        $customRepositoryClassName = $metadata->customRepositoryClassName;

        if ($customRepositoryClassName !== null) {
            $repository = new $customRepositoryClassName($this, $metadata);
        } else {
            $repository = new XmlEntityRepository($this, $metadata);
        }

        $this->repositories[$entityName] = $repository;

        return $repository;
    }