Need a method to convert app.storage Observables to builtin datatypes

[amks1]

I have a specific use case where I need to pickle and unpickle the storage data (specifically, app.storage.client) using dill.
dill.loads() throws this error:

AttributeError
'ObservableList' object has no attribute '_change_handlers'

ObservableCollection seems to recursively convert all inner dicts, lists, sets, etc into ObservableCollection datatypes. Can we have a method to convert them back into python builtin datatypes and get back the original data that was stored in them? In my case I don't need to modify the storage after unpickling.

[falkoschindler]

Thanks for the suggestion, @amks1!
Something like an extract() method would certainly be useful feature. Here's a quick proof of concept:

data = observables.ObservableDict({
    'a': 1,
    'b': [1, 2, 3, {'x': 1, 'y': 2, 'z': 3}],
    'c': {'x': 1, 'y': 2, 'z': 3, 't': [1, 2, 3]},
    'd': {1, 2, 3},
})

def extract(data):
    if isinstance(data, observables.ObservableDict):
        return {k: extract(v) for k, v in data.items()}
    if isinstance(data, observables.ObservableList):
        return [extract(v) for v in data]
    if isinstance(data, observables.ObservableSet):
        return {extract(v) for v in data}
    return data

print(extract(data))

{'a': 1, 'b': [1, 2, 3, {'x': 1, 'y': 2, 'z': 3}], 'c': {'x': 1, 'y': 2, 'z': 3, 't': [1, 2, 3]}, 'd': {1, 2, 3}}

I just wonder how to add correct type annotation.