def refresh(self, instance):
        return instance._meta.model.objects.get(pk=instance.pk)
Verify that L{Filehandle} implements L{IPushProducer}.
dataset/ETHPy150Open divio/cmsplugin-filer/cmsplugin_filer_tests_shared/base.py/CmsPluginsFilerBaseTestCase.refresh--crossover with--dataset/ETHPy150Open twisted/twisted/twisted/internet/test/test_iocp.py/IOCPReactorTests.test_fileHandleInterfaces