p><a class="source-toggle" href="#"
            onclick="toggleCode('M000027-source');return false;">[Source]</a></p>
          <div class="method-source-code" id="M000027-source">
<pre>
<span class="ruby-comment cmt"># File erubis/engine/escheme.rb, line 29</span>
    <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">add_preamble</span>(<span class="ruby-identifier">src</span>)
      <span class="ruby-keyword kw">return</span> <span class="ruby-keyword kw">unless</span> <span class="ru