code: public synchronized void merge(Model source) {
  		SimpleMerger merger = new SimpleMerger(
  			SimpleEditorMap.get(level));
  		if(source == null)
  			merger.merge(this, this); //repairs itself
  		else
  			merger.merge(this, source);
  	}
docs: This is default implementation that uses the
  id-based merging ({@link SimpleMerger#merge(Model, Model...)})
  
  NOTE: some applications, such as those dealing with persistence/transactions
  or advanced BioPAX alignment/comparison algorithms (like the Patch),
  may have to implement and use a more specific method instead.
  
  @see SimpleMerger
  @see Model#merge(Model)