de> by this resolver, before returning. If this property is not <code>true</code> after
 this method is called, the caller can safely assume no value was set.
 </p>

 <p>
 If this resolver was constructed in read-only mode, this method will always throw
 <code>PropertyNotWritableException</code>.
 </p>

 <p>
 If a <code>List</code> was created using <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/Collections.html?is-external=true#unmodifiableList(java.util.List)" title="class