+ /**
+ * Get an object from the database, referred to by reference timestamp key.
+ *
+ * @param <T> the type of the object to get, a subclass of {@link PfConcept}
+ * @param someClass the class of the object to get, a subclass of {@link PfConcept}
+ * @param key the PfReferenceTimestampKey of the object to get
+ * @return the object that was retrieved from the database or null if the object was not retrieved
+ */
+ <T extends PfConcept> T get(Class<T> someClass, PfReferenceTimestampKey key);
+