Merge nested dict recursively

merge_nested_dict.py

def merge(a:dict, b:dict, path=[]):
    for key in b:
        if key in a:
            if isinstance(a[key], dict) and isinstance(b[key], dict):
                merge(a[key], b[key], path + [str(key)])
            elif a[key] != b[key]:
                raise Exception('Conflict at ' + '.'.join(path + [str(key)]))
        else:
            a[key] = b[key]
    return a

dicts = [dict1, dict2,dict3]
merged_dict = reduce(merge, dicts)