tmask</span>(<span class="ruby-identifier">attribute</span>, <span class="ruby-identifier">options</span>={}, &amp;<span class="ruby-identifier">extension</span>)
  <span class="ruby-keyword">unless</span> <span class="ruby-identifier">options</span>[<span class="ruby-value">:as</span>] <span class="ruby-operator">&amp;&amp;</span> <span class="ruby-identifier">options</span>[<span class="ruby-value">:as</span>].<span class="ruby-identifier">kind_of?</span>(<span class="ruby-constant">Array</span>)
    <spa