="identifier">ConstPolygonRingIterator</span> <span class="identifier">range_begin</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">CustomPolygonRingRange</span><span class="special">&amp;</span> <span class="identifier">r</span><span class="special">)</span>
    <span class="special">{</span><span class="keyword">return</span> <span class="identifier">r</span><span class="special">.</span><span class="identifier">cbegin</span><span class="special">();}</span>
