="r"></span></p>
    <p class="run"><span class="n"><a id="t52" href="#t52">52</a></span><span class="t"><span class="op">@</span><span class="nam">contextlib</span><span class="op">.</span><span class="nam">contextmanager</span>&nbsp;</span><span class="r"></span></p>
    <p class="run"><span class="n"><a id="t53" href="#t53">53</a></span><span class="t"><span class="key">def</span> <span class="nam">change_dir</span><span class="op">(</span><span class="nam">new_dir</span><span class="op">)</span><span cl