ass="o">.</span><span class="n">date_range</span><span class="p">(</span><span class="n">start</span><span class="o">=</span><span class="s2">&quot;2000-01-01&quot;</span><span class="p">,</span> <span class="n">periods</span><span class="o">=</span><span class="n">nsample</span><span class="p">,</span> <span class="n">freq</span><span class="o">=</span><span class="s2">&quot;15min&quot;</span><span class="p">)</span>
    <span class="k">return</span> <span class="n">pd</span><span class="o">.</span><span c