code>member</code> and returns
<code>nil</code>.</p>

<p><strong>Postcondition:</strong> <code>self.intersect([member]).isEmpty</code></p>

    <h4>Declaration</h4>    
    <code class="language-swift">mutating func remove(member: Self.Element) -&gt; Self.Element?</code>
    
    
</div></div>
</div>
<div class="declaration" id="func-subtract_">
<a class="toggle-link" data-toggle="collapse" href="#comment-func-subtract_">func subtract(<wbr>_:)</a>
        
<div class="comment collapse" id="comment-func-subt