无法返回深层对象中的特定项

def get_value(obj, key):
    if isinstance(obj, dict):
        for k, v in obj.items():
            if k == key:
                return v
            elif isinstance(v, (dict, list)):
                result = get_value(v, key)
                if result is not None:
                    return result
    elif isinstance(obj, list):
        for item in obj:
            result = get_value(item, key)
            if result is not None:
                return result
    return None

data = {
    'foo': {
        'bar': {
            'baz': 42
        }
    },
    'spam': [
        {'eggs': 'ham'},
        {'eggs': 'spam'}
    ]
}

result = get_value(data, 'baz')
print(result)  # 输出：42

result = get_value(data, 'eggs')
print(result)  # 输出：ham

def get_value(obj, key):
    stack = [obj]
    while stack:
        current = stack.pop()
        if isinstance(current, dict):
            for k, v in current.items():
                if k == key:
                    return v
                elif isinstance(v, (dict, list)):
                    stack.append(v)
        elif isinstance(current, list):
            stack.extend(current)
    return None