>K</span>&gt;</span></span>
                  <span class="name ">keys</span>
          <div class="features">override</div>
</section>
        
                <section class="desc markdown">
          <p>The keys of <a href="dart-collection/MapView-class.html">this</a>.</p>
<p>The returned iterable has efficient <code>length</code> and <code>contains</code> operations,
based on <a href="dart-collection/MapView/length.html">length</a> and <a href="dart-collection/MapView/containsKey.html">containsKey</a> o