code: function makeLocalizeFunction(localization, nested) {
    return function localizeFunction(key) {
      return nested ? byString(localization, key) : localization[key];
    };
  }
docs: Convert the localization object into a function in case we need to support nested keys.
  
  @param {Object} localization the language object,
  @param {Boolean} nested
  
  @returns {Function}