python - tastypie obj_delete method does not work -

i have following code in tastypie. "obj_delete" method not work (will not invoked) 'contextresource' class. problem?

class contextresource(modelresource):     created_by = fields.foreignkey(userresource, 'created_by', full=true, null=true)     class meta:         queryset = context.objects.all()         resource_name = 'context'         authorization = djangoauthorization()         authentication = multiauthentication(basicauthentication(), sessionauthentication())         always_return_data = true         list_allowed_methods = ['get', 'post', 'put', 'delete']          filtering = {             "name": all,             "id": all,             "query":         }      def obj_create(self, bundle, **kwargs):         print '&& create context'         bundle.data['created_by'] = bundle.request.user         bundle = super(contextresource, self).obj_create(bundle, **kwargs)         self.create_xml(bundle)         return bundle      def obj_update(self, bundle, **kwargs):         bundle = super(contextresource, self).obj_update(bundle, **kwargs)         self.create_xml(bundle)         return bundle      def obj_delete(self, bundle, **kwargs):         print 'delete context'         bundle = super(contextresource, self).obj_delete(bundle, **kwargs)         context_generator = contextgenerator()         context_generator.delete(name=bundle.obj.name)         return bundle