public function setFormat($format)
    {
        $result = true;
        if (($this->debug === true) && !empty($this->evidence) && isset(Formats::$$this->evidence)) {
            if (array_key_exists($format, array_flip(Formats::$$this->evidence))
                === false) {
                $result = false;
            }
        }
        if ($result === true) {
            $this->format = $format;
            $this->updateApiURL();
        }
        return $result;
    }