Initializes a new FileDriver that looks in the given path(s) for mapping documents and operates in the specified operating mode.
string|array|FileLocator $locator A FileLocator or one/multiple paths where mapping documents can be found.:
string $fileExtension:
Overrides FileDriver::__construct
public function __construct($locator, $fileExtension = null) {
$fileExtension = ".php";
parent::__construct($locator, $fileExtension);
}