docs: public static void openUserCode(Function stub, Configuration parameters) throws Exception {
  		try {
  			FunctionUtils.openFunction(stub, parameters);
  		} catch (Throwable t) {
  			throw new Exception("The user defined 'open(Configuration)' method in " + stub.getClass().toString() + " caused an exception: " + t.getMessage(), t);
  		}
  	}