How to reinitialize a list with the default prompt value

ex: You have a custom list with Value variable 'country_code', Label variable 'country_code_label', Identifier 'id_country_code'

Here's the script to 'remove' the selected value, and set the custom list to its prompt message:

RMPApplication.setVariable("country_code","");
RMPApplication.setVariable("country_code_label","");
id_country_code.loadList();