="identifier">flat_map</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">flat_map</span><span class="special">&lt;</span> <span class="identifier">Key</span><span class="special">,</span> <span class="identifier">T</span> <span class="special">&gt;</span> <span class="special">&amp;</span> other<span class="special">)</span><span class="special">;</span></pre></li>
<li class="listitem"><pre class="literallayout"><span class="identifier">flat_map</span><span clas