docs: function Preferences(preferencesArray, namespace) {
      if (!preferencesArray) {
          throw new Error('Cannot create config. Must pass an array of properties!');
      }
      this.store = {};
      // store the keys we know
      this.keys = preferencesArray.map((item) => {
          this.store[item.key] = preference.newPreference(item.key, item.defaultValue, item.allowedValues, namespace);
          return item.key;
      });
  }