def test_sequenceOfStrings(self):
        """
        If C{showAttributes} is set to a sequence of strings, C{__str__}
        renders using those by looking them up as attributes on the object.
        """
        class Foo(util.FancyStrMixin):
            showAttributes = ("first", "second")
            first = 1
            second = "hello"
        self.assertEqual(str(Foo()), "<Foo first=1 second='hello'>")

        If C{showAttributes} is set to a sequence of strings, C{__str__}
        renders using those by looking them up as attributes on the object.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/test/test_util.py