Return the object 'd' in a JSON format.

        Manage the issue #815 for Windows OS

def _json_dumps(self, d):
        """Return the object 'd' in a JSON format.

        Manage the issue #815 for Windows OS
        """
        try:
            return json.dumps(d)
        except UnicodeDecodeError:
            return json.dumps(d, ensure_ascii=False)