span class="identifier">ConstPolygonRingIterator</span><span class="special">;</span>

<span class="keyword">class</span> <span class="identifier">CustomPolygonRingRange</span>
<span class="special">{</span>
    <span class="identifier">PolygonRingIterator</span> <span class="identifier">_begin</span><span class="special">;</span>
    <span class="identifier">PolygonRingIterator</span> <span class="identifier">_end</span><span class="special">;</span>

    <span class="keyword">bool</span> <span class="iden