def test_ednsVersion(self):
        """
        L{dns._EDNSMessage.ednsVersion} defaults to C{0} and can be overridden
        in the constructor.
        """
        self._verifyConstructorArgument(
            'ednsVersion', defaultVal=0, altVal=None)

        L{dns._EDNSMessage.ednsVersion} defaults to C{0} and can be overridden
        in the constructor.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_dns.py