private function getToken()
    {
        $vars = array(
            'method' => 'auth.getToken',
            'api_key' => $this->apiKey
        );

        $sig = $this->apiSig($this->apiSecret, $vars);
        $vars['api_sig'] = $sig;

        if ($call = $this->apiGetCall($vars)) {
            $this->token = $call->token;
        } else {
            return false;
        }
    }