def test_netInterfaces(self):
        """
        CompleteNetInterfaces produces zsh shell-code that completes system
        network interface names.
        """
        c = usage.CompleteNetInterfaces()
        out = c._shellCode('some-option', usage._ZSH)
        self.assertEqual(out, ':some-option:_net_interfaces')

        c = usage.CompleteNetInterfaces(descr='some action', repeat=True)
        out = c._shellCode('some-option', usage._ZSH)
        self.assertEqual(out, '*:some action:_net_interfaces')

        CompleteNetInterfaces produces zsh shell-code that completes system
        network interface names.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_usage.py