gistfile1.txt

  myRestrictedProp: function(key, value) {
    myAllowedValues = ['here', 'there'];
    if (value !== undefined) {
      if (myAllowedValues.indexOf(value) === -1) {
        throw "You tried to set a value that isn't allowed! " + value;
      } else {
        this._myRestrictedProp = value;
      }
    }

    return this._myRestrictedProp;
  }.property().cacheable()