def test_rcOrpreButNotBoth(self):
        """
        Release Candidate and prerelease can't both be given.
        """
        with self.assertRaises(ValueError):
            Version("whatever", 1, 0, 0,
                    prerelease=1, release_candidate=1)

        Release Candidate and prerelease can't both be given.
        
stackoverflow/venv/lib/python3.6/site-packages/incremental/tests/test_version.py