rray</span><span class="p">,</span> <span class="n">mask</span><span class="p">:</span> <span class="n">np</span><span class="o">.</span><span class="n">ndarray</span><span class="p">,</span> <span class="n">color</span><span class="p">:</span> <span class="nb">float</span><span class="p">,</span> <span class="n">alpha</span><span class="p">:</span> <span class="nb">float</span> <span class="o">=</span> <span class="mf">0.4</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">np</span