</span><span class="va">x</span><span class="op">)</span><span class="op">)</span><span class="op">{</span></span></span>
<span class="r-in"><span>    <span class="fu">stop_up</span><span class="op">(</span><span class="st">"Argument 'x' must be numeric but currently isn't."</span><span class="op">)</span></span></span>
<span class="r-in"><span>  <span class="op">}</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span>  <span class="co"># Now regular stop</span></span></span>