"arrow">&#45;&gt;</span></span>
  <span><span>string option</span> <span class="arrow">&#45;&gt;</span></span>
  <a href="#type-error_desc">error_desc</a></span></code></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-desc_registered_observer_being_deallocated"><a href="#val-desc_registered_observer_being_deallocated" class="anchor"></a><code><span><span class="keyword">val</span> desc_registered_observer_being_deallocated : 
  <span><a href="../../IR/Pvar/index.html#type-t">IR.Pva