def test_invalidNegative(self):
        """
        L{isIPAddress} should return C{False} for negative decimal values.
        """
        self.assertFalse(isIPAddress('-1'))
        self.assertFalse(isIPAddress('1.-2'))
        self.assertFalse(isIPAddress('1.2.-3'))
        self.assertFalse(isIPAddress('1.2.-3.4'))

        L{isIPAddress} should return C{False} for negative decimal values.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_abstract.py