public function rememberTopLevelContainers() {
		$result = [];
		$conditions = '(|(objectClass=organizationalUnit)(objectClass=container))';
		$fields = [CAKE_SETTINGS_APP_LDAP_ATTRIBUTE_DISTINGUISHED_NAME];
		$order = CAKE_SETTINGS_APP_LDAP_ATTRIBUTE_DISTINGUISHED_NAME;
		$limit = CAKE_SETTINGS_APP_TOP_LEVEL_UNITS_LIST_LIMIT;
		$scope = 'one';

		$data = $this->find('all', compact('conditions', 'fields', 'order', 'limit', 'scope'));
		if (empty($data)) {
			return $result;
		}

		$result = Hash::extract(
			$data,
			'{n}.' . $this->alias . '.' . CAKE_SETTINGS_APP_LDAP_ATTRIBUTE_DISTINGUISHED_NAME
		);

		return $result;
	}