

<span class="sd">    Returns:</span>
<span class="sd">      Integer if equivalent found (index to equiv element), None otherwise.</span>


<span class="sd">    See also:</span>
<span class="sd">      make_equiv</span>
<span class="sd">      is_equiv</span>
<span class="sd">      eq_in</span>
<span class="sd">    &quot;&quot;&quot;</span>

    <span class="k">for</span> <span class="n">i</span><span class="p">,</span> <span class="n">e</span> <span class="ow">in</span> <span class="nb">enumerate</span><spa