public function applyDecisionToUser($user_id, $decision_id, $source, $opts = array()) {
        $this->mergeArguments($opts, array(
            'account_id' => $this->account_id,
            'timeout' => $this->timeout,
            'decision_id' => $decision_id,
            'source' => $source,
            'analyst' => null,
            'description' => null,
            'time' => null
        ));

        $this->validateArgument($user_id, 'user_id', 'string');

        $url = ($this->api_endpoint .
            '/v3/accounts/' . rawurlencode($opts['account_id']) .
            '/users/'. rawurlencode($user_id) .
            '/decisions');

        return $this->applyDecision($url, $opts);
    }