public function setupToken($token)
    {
        if (!empty($token)) {
            $this->headers['Authorization'] = "Bearer $token";
            return true;
        } else {
            if ($this->throw_exceptions) {
                throw new CanvasPest_Exception(
                    'API authorization token must be a non-zero-length string',
                    CanvasPest_Exception::INVALID_TOKEN
                );
            }
            return false;
        }
    }