from ipdb import set_trace


def norm_list(ori_list,new_list):
    # new_list = []
    for item in ori_list:
        if not isinstance(item, list):
            new_list.append(ori_list)
            # return new_list
            break
        else:
            new_list = norm_list(item,new_list)
    return new_list

all = [[[1,2],[3,4]],[[2,3],[4,5]]]
new_list = []
new_list = norm_list(all,new_list)

print (new_list)