nn">datetime</span>
<span class="kn">from</span> <span class="nn">math</span> <span class="kn">import</span> <span class="n">floor</span>
<span class="kn">from</span> <span class="nn">typing</span> <span class="kn">import</span> <span class="n">Optional</span>

<span class="c1"># http://www.numpy.org/</span>
<span class="kn">import</span> <span class="nn">numpy</span> <span class="k">as</span> <span class="nn">np</span>

<span class="c1"># https://ipython.org/</span>
<span class="kn">from</span> <span class