Simple and safe way to get value of a nested dictionray

key_chain.py

def key_chain(data, *args, default=None): 
    for key in args:
        if isinstance(data, dict) and key in data:
            data = data[key]
        elif isinstance(data, (list, tuple)) and isinstance(key, int):
            try:
                data = data[key]
            except IndexError:
                return default
        else:
            return default
    return data

data = {
    'pets': [
        {
            'name' : 'Purrsloud',
            'species' : 'Cat',
            'favFoods' : ['wet food', 'dry food', '<strong>any</strong> food'],
            'birthYear' : 2016,
            'photo' : 'https://learnwebcode.github.io/json-example/images/cat-2.jpg'
        },
        {
            'name' : 'Barksalot',
            'species' : 'Dog',
            'birthYear' : 2008,
            'photo' : 'https://learnwebcode.github.io/json-example/images/dog-1.jpg'
        },
        {
            'name' : 'Meowsalot',
            'species' : 'Cat',
            'favFoods' : ['tuna', 'catnip', 'celery'],
            'birthYear' : 2012,
            'photo' : 'https://learnwebcode.github.io/json-example/images/cat-1.jpg'
        }
    ]
}

assert key_chain(data, 'pets', 0, 'species') == 'Cat'
assert key_chain(data, 'pets', 1, 'birthYear') == 2008
assert key_chain(data, 'pets', 2, 'favFoods', 0) == 'tuna'
assert key_chain(data, 'pets', 3) is None
assert key_chain(data, 10) is None
assert key_chain(data, 'pets', 2, 'favFoods', 4) is None
assert key_chain(data, 'pets', 2, 'favFoods', 4, default='cookies') == 'cookies'
assert key_chain(data, 'pets', 0, 'mood') is None
assert key_chain(data, 'pets', -1, 'name') == 'Meowsalot'
assert key_chain(data, 'pets', -1, -1) is None
assert key_chain(data, 7) is None
assert key_chain(1, 2) is None
assert key_chain('kittie', 2) is None
assert key_chain(data, 'pets', 2, 'favFoods') == ['tuna', 'catnip', 'celery']
assert key_chain(data, *range(10000)) is None