def _verifyConstructorArgument(self, argName, defaultVal, altVal):
        """
        Wrap L{verifyConstructorArgument} to provide simpler interface for
        testing Message and _EDNSMessage constructor arguments.

        @param argName: The name of the constructor argument.
        @param defaultVal: The expected default value.
        @param altVal: An alternative value which is expected to be assigned to
            a correspondingly named attribute.
        """
        verifyConstructorArgument(testCase=self, cls=self.messageFactory,
                                  argName=argName, defaultVal=defaultVal,
                                  altVal=altVal)

        Wrap L{verifyConstructorArgument} to provide simpler interface for
        testing Message and _EDNSMessage constructor arguments.

        @param argName: The name of the constructor argument.
        @param defaultVal: The expected default value.
        @param altVal: An alternative value which is expected to be assigned to
            a correspondingly named attribute.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_dns.py