protected function _loadAclAdapter($adapter) {
		if (!class_exists($adapter)) {
			throw new Exception(sprintf('The Acl Adapter class "%s" was not found.', $adapter));
		}

		$adapterInstance = new $adapter();
		if (!($adapterInstance instanceof AclAdapterInterface)) {
			throw new InvalidArgumentException(sprintf(
				'TinyAuth Acl adapters have to implement %s.', AclAdapterInterface::class
			));
		}

		return $adapterInstance;
	}