code: public Set<XExtension> getExtensions() {
  		if (attributes != null) {
  			return XAttributeUtils.extractExtensions(getAttributes());	
  		} else {
  			return Collections.emptySet();
  		}
  	}
docs: /*
  (non-Javadoc)
  
  @see org.deckfour.xes.model.impl.XAttribute#getExtensions()