an>
<span class="r-in"><span><span class="va">x</span> <span class="op">&lt;-</span> <span class="cn">NA_integer_</span></span></span>
<span class="r-in"><span><span class="fu">check_positive</span><span class="op">(</span><span class="va">x</span><span class="op">)</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="co"># `x` must be larger than 0</span></span></span>
<span class="r-in"><span><span class="va">x</span> <span class="op">&lt;-</span> <span class=