JSON to YAML conversion

converter.py

from ruamel.yaml import YAML
import json
from pathlib import Path
import sys
from collections import OrderedDict
import collections
from ruamel.yaml.comments import CommentedMap

def convert(filename):
    yaml = YAML()
    yaml.default_flow_style = False
    yaml.indent(mapping=2, sequence=4, offset=2)
    original = Path(filename)
    target = original.with_suffix(".yml")
    with original.open("r") as f:
        data = json.load(f, object_pairs_hook=lambda x: CommentedMap(OrderedDict(x)))
    with target.open("w") as f:
        yaml.dump(data, f)

if __name__ == "__main__":
    convert(sys.argv[1])

The object_pairs_hook is only relevant for Python 3 older than 3.6 where dicts have undetermined order.