n sub-classes.</p>

    <code class="phpdocumentor-code phpdocumentor-signature ">
    <span class="phpdocumentor-signature__visibility">protected</span>
                <span class="phpdocumentor-signature__name">_validate</span><span>(</span><span class="phpdocumentor-signature__argument"><span class="phpdocumentor-signature__argument__return-type">string&nbsp;</span><span class="phpdocumentor-signature__argument__name">$rs</span></span><span>)</span><span> : </span><span class="phpdocumentor-signature__r