def test_loadByNamesDuplicate(self):
        """
        Check that loadByNames ignores duplicate names
        """
        module = 'twisted.trial.test.test_log'
        suite1 = self.loader.loadByNames([module, module], True)
        suite2 = self.loader.loadByName(module, True)
        self.assertSuitesEqual(suite1, suite2)

        Check that loadByNames ignores duplicate names
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_loader.py