class="p">,</span>
        <span class="s1">&#39;OPTIONS&#39;</span><span class="p">:</span> <span class="p">{</span>
             <span class="s1">&#39;string_if_invalid&#39;</span><span class="p">:</span> <span class="s1">&#39;Invalid varialbe!&#39;</span><span class="p">,</span>
         <span class="p">}</span>
    <span class="p">},</span>
<span class="p">]</span>
</pre></div>
</div>
</div>
<div class="section" id="references">
<h2>References<a class="headerlink" href="#references" title="Permalink to 