public function find_all() {
        $this->ensure_path_exists();
        $files = glob($this->glob_keys_pattern(), GLOB_MARK | GLOB_NOSORT);
        $return = array();
        if ($files === false) {
            return $return;
        }
        foreach ($files as $file) {
            $return[] = substr(basename($file), 0, -6);
        }
        return $return;
    }