public function getModel($filename)
    {
        $filename = Files::concatenatePaths([$this->cldrBasePath, $filename . '.xml']);

        if (isset($this->models[$filename])) {
            return $this->models[$filename];
        }

        if (!is_file($filename)) {
            return false;
        }

        return $this->models[$filename] = new CldrModel([$filename]);
    }