787 </span><span class="s1">&#39;</span> ]
    <span class="o">!</span> <span class="k">if</span> <span class="nv">string</span> <span class="nv">is</span> <span class="nv">nothing</span> <span class="nv">but</span> <span class="nv">digits</span> <span class="nv">and</span> <span class="nv">whitespace</span> <span class="k">return</span> .<span class="nv">true</span>.
    <span class="k">do</span> <span class="nv">i</span><span class="o">=</span><span class="mi">1</span>,<span class="nv">size</span><span cl