l">&lt;</span>
    <span class="keyword">class</span> <span class="identifier">M</span><span class="special">&gt;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span><span class="special">&lt;</span> <span class="identifier">iterator</span><span class="special">,</span> <span class="keyword">bool</span> <span class="special">&gt;</span>
<span class="identifier">insert_or_assign</span><span class="special">(</span>
    <span class="identifier">string_v