{
  void set() { }
}</pre>


<h3>Concept Checking Class</h3>

<pre>  template &lt;class PMap, class Key&gt;
  struct WritablePropertyMapConcept
  {
    typedef typename property_traits&lt;PMap&gt;::key_type key_type;
    typedef typename property_traits&lt;PMap&gt;::category Category;
    typedef boost::writable_property_map_tag WritableTag;
    void constraints() {
      function_requires&lt; ConvertibleConcept&lt;Category, WritableTag&gt; &gt;();
      put(pmap, k, val);
    }
    PMap pmap;
    Key k;
  