code: @Override
  	public void createIsEmptyFunction() {
  		createFunction(IS_EMPTY_FUNCTION, new GeometryFunction() {
  			@Override
  			public Object execute(GeoPackageGeometryData data) {
  				return data == null || data.isEmpty()
  						|| data.getGeometry() == null;
  			}
  		});
  	}
docs: {@inheritDoc}