rror_desc</a></code></dt><dt class="spec value" id="val-desc_retain_cycle"><a href="#val-desc_retain_cycle" class="anchor"></a><code><span class="keyword">val</span> desc_retain_cycle : string <span>&#45;&gt;</span> <a href="../IBase/Location/index.html#type-t">IBase.Location.t</a> <span>&#45;&gt;</span> <span>string option</span> <span>&#45;&gt;</span> <a href="index.html#type-error_desc">error_desc</a></code></dt><dt class="spec value" id="val-desc_registered_observer_being_deallocated"><a href="#val-desc