code: def create(cls, user, **kwargs):
          
          parent_id = kwargs.get(cls.parent_resource.resource_type + '_id')
          try:
              parent = yield cls.parent_resource.get(parent_id)
          except couch.NotFound:
              msg = 'Parent {} with id {} not found'.format(
                  cls.parent_resource.resource_type,
                  parent_id)
              raise exceptions.ValidationError(msg)
  
          if not parent.editable:
              err = 'Cannot create child of {} resource'.format(parent.state.name)
              raise exceptions.Unauthorized(err)
  
          resource = yield super(SubResource, cls).create(user, **kwargs)
          resource._parent = parent
  
          raise Return(resource)
docs: If parent resource is not an editable state, should not be able to create.