flatten.py

d = {
    "a1": {
        "b1": {
            "c1": {4, 5},
            "c2": "123",
            "c3": tuple(),
            "c4": 100_000,
            "c5": 1 ** 200000,
        },
        "b2": "something else",
        "b3": 10,
    },
    "a2": None,
    "a3": -1,
}


def flatten(d):
    for k, v in d.items():
        if isinstance(v, dict):
            for other_keys, sub_val in flatten(v):
                yield (k, *other_keys), sub_val
        else:
            yield (k,), v


for k, v in flatten(d):
    print(f"{str(k):>30} {v}")

# ('a1', 'b1', 'c1') {4, 5}
# ('a1', 'b1', 'c2') 123
# ('a1', 'b1', 'c3') ()
# ('a1', 'b1', 'c4') 100000
# ('a1', 'b1', 'c5') 1
#       ('a1', 'b2') something else
#       ('a1', 'b3') 10
#            ('a2',) None
#            ('a3',) -1