def test_str(self):
        """
        The C{__str__} for L{UnsupportedMethod} makes it clear that what it
        shows is a list of the supported methods, not the method that was
        unsupported.
        """
        b = "b" if _PY3 else ""
        e = error.UnsupportedMethod([b"HEAD", b"PATCH"])
        self.assertEqual(
            str(e), "Expected one of [{b}'HEAD', {b}'PATCH']".format(b=b),
        )

        The C{__str__} for L{UnsupportedMethod} makes it clear that what it
        shows is a list of the supported methods, not the method that was
        unsupported.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_error.py