def test_deprecated(self):
        """
        L{twisted.conch.ssh.common.install} is deprecated.
        """
        common.install()
        warnings = self.flushWarnings([self.test_deprecated])
        self.assertEqual(len(warnings), 1)
        self.assertEqual(
            warnings[0]["message"],
            "twisted.conch.ssh.common.install was deprecated in Twisted 16.5.0"
        )

        L{twisted.conch.ssh.common.install} is deprecated.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_ssh.py