code: public void closeRetainGeoPackages(Collection<String> retain) {
  		Set<String> close = new HashSet<>(propertiesMap.keySet());
  		close.removeAll(retain);
  		for (String name : close) {
  			closeGeoPackage(name);
  		}
  	}
docs: Close GeoPackages not specified in the retain GeoPackage names
  
  @param retain
  GeoPackages to retain