   <span class="c1"># First iteration</span>
    <span class="n">Y_i</span> <span class="o">=</span> <span class="n">spec</span>
    <span class="n">y_i</span> <span class="o">=</span> <span class="n">lsee_mstft</span><span class="p">(</span><span class="n">Y_i</span><span class="p">,</span> <span class="n">syn_hop</span><span class="o">=</span><span class="n">syn_hop</span><span class="p">,</span> <span class="n">win_length</span><span class="o">=</span><span class="n">win_length</span><span class="p">,</s