Update() is broken as of 3.4.3

Given this sample code:

import box

if __name__ == '__main__':
    b = box.Box({
        'one': {
            'sub1': 'monkey',
            'sub2': 'goat',
        }
    }, box_it_up = True)

    print(f'box: {b}')
    print(f'one is a {type(b.one)}')
    print(f'expect monkey: {b.one.sub1}')
    print(f'expect goat: {b.one.sub2}')
            
    b.update({'one': {'sub2': 'alpaca'}})
    print(f'one is a {type(b.one)}')
    print(f'expect monkey: {b.one.sub1}')
    print(f'expect alpaca: {b.one.sub2}')

It works with < 3.4.3:

box: {'one': {'sub1': 'monkey', 'sub2': 'goat'}}
one is a <class 'box.Box'>
expect monkey: monkey
expect goat: goat
one is a <class 'box.Box'>
expect monkey: monkey
expect alpaca: alpaca

But using >= 3.4.3, this is the result:

box: {'one': {'sub1': 'monkey', 'sub2': 'goat'}}
one is a <class 'box.Box'>
expect monkey: monkey
expect goat: goat
one is a <class 'dict'>
Traceback (most recent call last):
  File "./test.py", line 16, in <module>
    print(f'expect monkey: {b.one.sub1}')
AttributeError: 'dict' object has no attribute 'sub1'

I notice there were changes to the update() method.

(edited: added some code to print out the types, which show the difference)

[alertedsnake]

Hooray:

box: {'one': {'sub1': 'monkey', 'sub2': 'goat'}}
one is a <class 'box.Box'>
expect monkey: monkey
expect goat: goat
one is a <class 'box.Box'>
expect monkey: monkey
expect goat: alpaca

Looks great! Thanks for the quick work on this, and for the excellent library!

[alertedsnake]

Thanks! It actually took me about an hour to dig in enough to find the cause - we subclass Box with a bunch of extra logic, so there were a lot of places it could have been.