         Observable self, name, new fn()
         #LazyObservable self, name, lazy_single_get_fn, relation_params
 
-      self[name + '_get'] = single_get_fn.apply self, relation_params
+      self[name + '_get'] = Helpers.single_get_fn.apply self, relation_params
 
   # Multiple relations
   # Generated methods:

      else
        ObservableArray self, name + 's', []
        #LazyObservableArray self, name + 's', lazy_get_fn, relation_params
      self[name + '_get'] = get_fn.apply self, relation_params

      # Create
      #
      self[name + '_add'] = create_fn.apply self, relation_params

      # Destroy
      #
      self[name + '_destroy'] = destroy_fn.apply self, relation_params

      object_merge data,
        model: name.capitalize()

      relation_params = Helpers.relationship_fields name, data.model, self.api(), options

      fn = window[data.model]
      fn = data.model if data.model? and typeof data.model == 'function'

      if typeof fn != 'function'
        console.debug 'Relation model for "' + name + '" not a function: ', fn
        throw new Error 'No model for has_one/belongs_to relation found'

      if typeof self[name + '_id'] != 'function' && name not in options.belongs_to
