AWS Cloudformation template manipulation based on: https://stackoverflow.com/questions/50914422/parse-an-aws-cloudformation-template-with-the-pyyaml-library

parser.py

from cfn_tools import load_yaml
import cfn_flip.yaml_dumper
from cfn_flip import to_json

import yaml
import json

with open('k8s-cluster.yaml') as f:
    raw = f.read()
    print(type(raw))
    data_dict = load_yaml(raw)
    json_resource = to_json(raw)

obj_dict = json.loads(json_resource)
obj_dict["Resources"]["k8svpc"]["Properties"]["Tags"].append({
    "Key": "aaaa",
    "Value": "bbbb"
})

print(obj_dict["Resources"]["k8svpc"]["Properties"]["Tags"])

with open('output.template', 'w') as f:
    dumper = cfn_flip.yaml_dumper.get_dumper(clean_up=False, long_form=False)
    data_dict = load_yaml(json.dumps(obj_dict))
    raw = yaml.dump(
        data_dict,
        Dumper=dumper,
        default_flow_style=False,
        allow_unicode=True
    )
    f.write(raw)