   <section class="desc markdown">
      <p>Retrieves the zone-value associated with <code>key</code>.</p>
<p>If this zone does not contain the value looks up the same key in the
parent zone. If the <code>key</code> is not found returns <code>null</code>.</p>
<p>Any object can be used as key, as long as it has compatible <code>operator ==</code>
and <code>hashCode</code> implementations.
By controlling access to the key, a zone can grant or deny access to the
zone value.</p>
    </section>
    
    <section