code: function() {
      var self = this;
      var relationKey = this._name + 'Relation';
      var unconfiguredRelationKey = '_' + relationKey;
      return _.object([
        [relationKey, property(function() { return self.configured(); })],
        [unconfiguredRelationKey, property(function() { return self; })],
      ]);
    }
docs: All relations define a `<name>Relation` method that is used to access the
  relation from model classes (and instances) & also to dispatch individual
  method calls. This simply adds the method that returns the configured
  relation object (though it can be overridden by subclasses or individual
  instances).
  
  Subclasses can override this.
  
  @method
  @public
  @scope internal
  @return {Object}