ode class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">bidirectional_iterator_tag</span></code>. Otherwise,
        if <code class="computeroutput"><span class="identifier">Iterator</span></code> models Readable
        Lvalue Iterator and Forward Traversal Iterator then <code class="computeroutput"><span class="identifier">iterator_category</span></code>
        is convertible to <code class="computeroutput"><span class="identifier">std</span><