Проблема форматирования SnakeYAML

Question

Мой файл yaml выглядит следующим образом:

!!yamlDemo.YamlConfig
receivers:
- email_config:
    auth_identity: rorajesh19940318@gmail.com
    auth_password: rajesh@123
    auth_username: rorajesh19940318@gmail.com
    from: rorajesh19940318@gmail.com
    smarthost: smtp.gmail.com:587
    to: abhi.mmmc@gmail.com
  name: Abhishek
route:
  group_by:
  - g1
  - g2
  group_interval: 10s
  group_wait: 10s
  receiver: Abhishek
  repeat: 4h
routes:
- match:
    criticality: c
    receiver: Abhishek
    site: A

Я хочу, чтобы файл выглядел следующим образом

!!yamlDemo.YamlConfig
receivers:
- email_config:
    auth_identity: rorajesh19940318@gmail.com
    auth_password: rajesh@123
    auth_username: rorajesh19940318@gmail.com
    from: rorajesh19940318@gmail.com
    smarthost: smtp.gmail.com:587
    to: abhi.mmmc@gmail.com
  name: Abhishek
route:
  group_by:[g1,g2],
  group_interval: 10s
  group_wait: 10s
  receiver: Abhishek
  repeat: 4h
routes:
- match:
    criticality: c
    receiver: Abhishek
    site: A