>
    <span class="k">if</span> <span class="n">extent</span><span class="p">:</span>
        <span class="n">x_min</span><span class="p">,</span> <span class="n">x_max</span><span class="p">,</span> <span class="n">y_min</span><span class="p">,</span> <span class="n">y_max</span> <span class="o">=</span> <span class="n">extent</span>
        <span class="n">x_array</span> <span class="o">=</span> <span class="n">x_array</span><span class="p">[(</span><span class="n">x_array</span> <span class="o">&gt;=</sp