public function load($resources, $extension = '')
    {
        $finder = new Finder();
        $collection = array();

        if (is_array($resources)) {
            foreach ($resources as $resource) {
                $subcollection = array();
                $subcollection = $this->load($resource);
                $collection = array_merge($collection, $subcollection);
            }
        } elseif (is_dir($resources)) {
            $files = $finder->files()->name('*'.$extension)->in($resources);
            foreach ($files as $file) {
                $collection[] = realpath($file->getPathName());
            }
        } elseif (is_file($resources)) {
            $collection = array(realpath($resources));
        } else {
            throw new \InvalidArgumentException('Argument must be an absolute directory or a file path or both in an array');
        }

        return $collection;
    }