How to pass Dict/JSON like object to macross from iframe

hi, I wrote a macro that replaces value of userfields, it works but only with text (str), when i try send array (dict in python) to macros i got NoneType error for object1 array.

            function CheckDictPass() {
            const object1 = {"FIO": 1, "FIO2": 2, "FIO22": 3};
            window.frames[0].postMessage(JSON.stringify({'MessageId': 'Host_PostmessageReady'}), '*')
                        'MessageId': 'CallPythonScript',
                        'ScriptFile': '',
                        'Function': 'replace_userfield3',
                        'Values': {

                            - works
                            'userfield_name': {'type': 'string', 'value': userfield_name},
                            'userfield_value': {'type': 'string', 'value': userfield_value},
                             - don't work NoneType error
                            'dataset': {'type': 'object', 'value': object1},