How defining a group

I want to define my first group of switches…

switch:
  - platform: group
    name: Sfeerverlichting
    entities:
      - switch.sfeerverlichting_dressoir
      - switch.sfeerverlichting_links
      - switch.sfeerverlichting_rechts

But the configuration validation says

Invalid config for [group]: value should be a string for dictionary value @ data[‘group’][‘switch’][‘entities’]. Got None. (See /config/configuration.yaml, line 8).

What’s the problem…must be something stupid, but… ?

I don’t think a switch with platform: group is valid. The documentation does not seem to mention that anywhere. There’s a light group and a group, but no switch group.

OK, I define it as this and no error anymore

group:
  name: Sfeerverlichting
  entities:
    - switch.sfeerverlichting_dressoir
    - switch.sfeerverlichting_links
    - switch.sfeerverlichting_rechts

But now, how can I replace the different entities in my automatisations by this group ?

alias: Sfeerverlichting 's avonds inschakelen
description: ''
trigger:
  - platform: sun
    event: sunset
    offset: '-01:30'
condition:
  - condition: and
    conditions:
      - condition: state
        entity_id: input_boolean.toggle_op_vakantie
        state: 'off'
      - condition: and
        conditions:
          - condition: state
            entity_id: input_boolean.toggle_sfeerverlichting_s_avonds
            state: 'on'
action:
  - type: turn_on
    device_id: 7a74e8a0e5c59427d4dd08b85a25577b
    entity_id: switch.sfeerverlichting_dressoir
    domain: switch
  - type: turn_on
    device_id: daec5c6545b70ab1e2a1aa4954463ce6
    entity_id: switch.sfeerverlichting_links
    domain: switch
  - type: turn_on
    device_id: dd77e7fcd8e29c8129905d5b77f148d9
    entity_id: switch.sfeerverlichting_rechts
    domain: switch
mode: single

You can call homeassistant.turn_on with your group as the entity_id.

Thank you !

action:
  - service: homeassistant.turn_on
    target:
      entity_id: group.group