code: public XAttributeLiteral createAttributeLiteral(String key, String value,
  			XExtension extension) {
  		return new XAttributeLiteralImpl(intern(key), intern(value), extension);
  	}
docs: /* (non-Javadoc)
  @see org.deckfour.xes.model.factory.XModelFactory#createAttributeLiteral(java.lang.String, java.lang.String, org.deckfour.xes.extension.XExtension)