>>> import json
>>> 
>>> class Model:
...     a = 1
...     b = 2
...     def save(self):
...         dct = {k: str(v) for k, v in vars(Model).items()}
...         with open('file.txt', 'w', encoding='utf-8') as fout:
...             json.dump(dct, fout)
... 
>>> obj = Model()
>>> obj.save()
>>> 
>>> 
[guest@localhost py]$ cat file.txt 
{"__module__": "__main__", "a": "1", "b": "2", "save": "<function Model.save at 0x7f9650a8f400>", "__dict__": "<attribute '__dict__' of 'Model' objects>", "__weakref__": "<attribute '__weakref__' of 'Model' objects>", "__doc__": "None"}[guest@localhost py]$ 
[guest@localhost py]$