ed.
Returns <code>null</code> if <code>key</code> was not in the map.</p>
<p>Note that values can be <code>null</code> and a returned <code>null</code> value doesn't
always mean that the key was absent.</p>
    </section>
    
    <section class="summary source-code" id="source">
      <h2><span>Implementation</span></h2>
      <pre class="language-dart"><code class="language-dart">V? remove(Object? key) {
  if (!_validKey(key)) return null;
  _SplayTreeMapNode&lt;K, V&gt;? mapRoot = _remove(key as dynamic)