Problem with optional input

Configuration Blueprints
1

I’m not able to set an optional input without error. This is my code:

blueprint:
  name: test
  description: "\n#"
  domain: automation
  input:
    timer1:
      name: Timer1
      description: Timer entity.
      default: []
      selector:
        entity:
          domain: timer
          multiple: true
trigger:
  - platform: state
    entity_id:
      - !input timer1
    to: idle
    id: timer
condition: []
variables:
  timer1: !input timer1
action:
  - choose:
      - conditions:
          - condition: trigger
            id: timer
        sequence:
          - service: notify.persistent_notification
            data:
              message: "just a test"
mode: parallel

If I leave the input empty while creating the automation, it gives this error:

Message malformed: Entity [] is neither a valid entity ID nor a valid UUID for dictionary value @ data['entity_id']

What am I making bad?
Thanks

2

I answer myself. The correct blueprint is this:

blueprint:
  name: test
  description: "\n#"
  domain: automation
  input:
    timer1:
      name: Timer1
      description: Timer entity.
      default: []
      selector:
        entity:
          domain: timer
          multiple: true
trigger:
  - platform: state
    # Next line changes
    entity_id: !input timer1
    to: idle
    id: timer
condition: []
variables:
  timer1: !input timer1
action:
  - choose:
      - conditions:
          - condition: trigger
            id: timer
        sequence:
          - service: notify.persistent_notification
            data:
              message: "just a test"
mode: parallel