Vacuum Send_command with multiple Variables from state_atr

Configuration
1

Hi there,

i try to send my vaccum to multiple rooms by room numbers. Manually it works:

- id: '16727600974342'
  alias: Mai_Linh WoZi
  description: ''
  trigger:
  - platform: state
    entity_id: []
  condition: []
  action:
  - service: vacuum.send_command
    data:
      command: spot_area
      params:
        rooms: 6, 1
        cleanings: 1
    target:
      entity_id: vacuum.mai_linh

The numbers 6 and 1 can be found at:
{{ state_attr(‘vacuum.mai_linh’, ‘rooms’)[‘bathroom’]}}
and
{{ state_attr(‘vacuum.mai_linh’, ‘rooms’)[‘kitchen’]}}

Unfortunately i dont get it done to extract the numbers and send it via the automation like:

        rooms: >
          {{ state_attr('vacuum.mai_linh', 'rooms')['bathroom'] }}, {{state_attr('vacuum.mai_linh', 'rooms')['kitchen'] }}
        cleanings: 1

i hope someone can get me a hint, didnt been succesful on the web.