Dictionary list product expansion

dict_expand.py

from functools import reduce
from copy import deepcopy
from itertools import product


def get_key_paths(d, key_paths=[], param_lists=[], acc=[]):
    for k, v in d.items():
        if isinstance(v, dict):
            get_key_paths(v, key_paths, param_lists, acc=acc + [k])
        elif isinstance(v, list):
            key_paths.append(acc + [k])
            param_lists.append(v)

    return key_paths, param_lists

def set_key_path(d, key_path, v):
    d1 = reduce(dict.get, key_path[:-1], d)
    d1[key_path[-1]] = v


config = {
    'L1key1': [0, 1, 2],
    'L1key2': {
        'L2key1': 1,
        'L2key2': [4, 5, 6],
    }
}

key_paths, param_lists = get_key_paths(config)

param_prod = product(*param_lists)
for params in param_prod:
    config_copy = deepcopy(config)
    for key_path, param in zip(key_paths, params):
        set_key_path(config_copy, key_path, param)

    print(config_copy)