p://www.boost.org/libs/python/doc/v2/class.html#class_-spec">class_</a> template, whose “signature” is:</p>
<pre class="literal-block">
template class&lt;
    ValueType, BaseList = bases&lt;&gt;
  , HeldType = ValueType, Copyable = void
&gt;
class class_;
</pre>
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<p>Only the first argument, <tt class="docutils literal">ValueType</tt>, is required.</p>
<div class="section" id="named-template-parameters">
<h3>2.4.1&nbsp;&nbsp;&nbsp;Named Template Parameters</h3>
<p>First, we'll build an 