Python dict deep merge

deep_merge.py

from copy import deepcopy
from functools import reduce


def merge_dicts(dict1: dict, dict2: dict) -> dict:
    """
    Merges dicts.
    """
    for key in dict2:
        if key not in dict1 or not isinstance(dict1[key], dict):
            dict1[key] = deepcopy(dict2[key])
        else:
            dict1[key] = merge_dicts(dict1[key], dict2[key])
    return dict1


def deep_merge_dicts(*dicts: dict, update: bool = False) -> dict:
    """
    Merges dicts deeply.
    """
    if update:
        return reduce(merge_dicts, dicts[1:], dicts[0])
    return reduce(merge_dicts, dicts, {})