如何从嵌套字典中筛选和读取值和键？

def get_value_from_nested_dict(nested_dict, keys):
    if not keys:
        return nested_dict
    key = keys[0]
    if key in nested_dict:
        value = nested_dict[key]
        if len(keys) == 1:
            return value
        if isinstance(value, dict):
            return get_value_from_nested_dict(value, keys[1:])
    return None

nested_dict = {
    'a': {
        'b': {
            'c': 1,
            'd': 2
        },
        'e': 3
    },
    'f': {
        'g': {
            'h': 4
        }
    }
}

keys = ['a', 'b', 'c']
value = get_value_from_nested_dict(nested_dict, keys)
print(value)  # 输出 1

keys = ['f', 'g', 'h']
value = get_value_from_nested_dict(nested_dict, keys)
print(value)  # 输出 4

keys = ['x', 'y', 'z']
value = get_value_from_nested_dict(nested_dict, keys)
print(value)  # 输出 None