code: public static Entity toEntity(Lock lock, com.google.appengine.api.datastore.Key parent) {
  		Entity entity = new Entity(LOCK_KIND, lock.id(), parent);
  		entity.setUnindexedProperty(TRANSACTION_PROPERTY, lock.transaction());
  		entity.setUnindexedProperty(TIMESTAMP_PROPERTY, lock.timestamp());
  		return entity;
  	}
docs: Translates Acid House {@code Lock} entity to Google App Engine Datastore
  entity with the specified {@code Key} of parent.
  
  @param lock Acid House {@code Lock} entity.
  @param parent The {@code Key} of parent.
  @return Google App Engine Datastore entity translated from Acid House
  {@code Lock} entity.