--- a/src/twisted/python/test/test_setup.py 2018-09-13 19:23:17.219592749 +0530 +++ b/src/twisted/python/test/test_setup.py 2018-09-13 19:25:02.451597309 +0530 @@ -92,7 +92,7 @@ class OptionalDependenciesTests(TestCase The extras need to be parsed with pkg_resources.parse_requirements(), which returns a generator. """ - extras = dict(im_an_extra_dependency="thing") + extras = dict(im_an_extra_dependency=["thing"]) attrs = dict(extras_require=extras) distribution = Distribution(attrs)