sd">    Args:</span>
<span class="sd">       xf (array): frequency array from FFT.</span>
<span class="sd">       yf (array): normalized FFT values.</span>

<span class="sd">    Returns:</span>
<span class="sd">       (float): maxfreq, the maximum frequency above threshold in fourier spectrum.</span>

<span class="sd">    &quot;&quot;&quot;</span>

    <span class="n">check</span> <span class="o">=</span> <span class="mi">0</span>
    <span class="k">for</span> <span class="n">i</span> <span class="ow">in</