><span id="L-68"><a href="#L-68"><span class="linenos">68</span></a>                             <span class="sa">f</span><span class="s1">&#39; samples of &quot;x&quot; is not equal to the number of samples of &quot;y&quot;...&#39;</span><span class="p">)</span>
</span><span id="L-69"><a href="#L-69"><span class="linenos">69</span></a>        <span class="k">if</span> <span class="ow">not</span> <span class="nb">isinstance</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><s