Have a nested dictionary.

stock_price = {'lastPrice': 129.1,
    'open': 126.57,
    'close': 0,
    'intraDayHighLow': {'min': 126.4, 'max': 129.55, 'value': 129.1},
    'weekHighLow': {'min': 49.7, 'minDate': '26-Jun-2023', 
       'max': 142.9,
       'maxDate': '30-Apr-2024',
        'value': 129.1},
    }

…which is converted it to a dataclass, as follows.

from dataclasses import dataclass
def create_dataclass_from_dict(data_dict: dict, class_name:str):

    fields = {}
    
    for key, value in data_dict.items():
        if isinstance(value, dict):
            nested_class_name = key.capitalize()
            nested_class = create_dataclass_from_dict(value, class_name=nested_class_name)
            fields[key] = nested_class
        else:
            fields[key] = value
    
    return dataclass(type(class_name, (), fields))

….but when I see the dict of the instance, it shows an empty set…

Stock = create_dataclass_from_dict(stock_price, 'Stock')

my_stock = Stock()
my_stock.__dict__ # gives {}

…and so not able to convert it back to a dictionary using the following code:

import json
def to_dict(obj):
    return json.loads(json.dumps(obj, default=lambda o: o.__dict__))

to_dict(my_stock) # gives {}

Where am I going wrong? Why is the .__dict__ empty?