private function parseFile($path)
    {
        try {
            $classes = $this->yamlParser->parseFile($path, Yaml::PARSE_CONSTANT);
        } catch (ParseException $e) {
            throw new \InvalidArgumentException(sprintf('The file "%s" does not contain valid YAML.', $path), 0, $e);
        }

        // empty file
        if (null === $classes) {
            return [];
        }

        // not an array
        if (!\is_array($classes)) {
            throw new \InvalidArgumentException(sprintf('The file "%s" must contain a YAML array.', $this->file));
        }

        return $classes;
    }