an><span class="nf">clear</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="w">        </span><span class="sd">&quot;&quot;&quot;Clear all video and audio tracks in the stack&quot;&quot;&quot;</span>
        <span class="k">while</span> <span class="nb">len</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">tracks</span><span class="p">):</span>
            <span class="nb">print</span> <span class="p">(</span><spa