Example

$form->addAltcha();

// or with SPAM Filter enabled:
$form->addAltcha(true);

<div class="row">
    <div class="offset-sm-4 col-sm-8 mb-3">
        <altcha-widget id="altcha_10fe99e967bfeb81" challengeurl="https://eu.altcha.org/api/v1/challenge?apiKey=ckey_01093d9331f025a8e41251bf1f9d">
        </altcha-widget>
        <br>
    </div>
</div>