[solved] Syntax for script with service_template. Can't find the right way to define entity

[petro]

Service templates require a result at all times, so you have to use a condition to stop the script instead of using a service template.

script:
  media_mode:
  alias: Set media mode script 
  sequence:
  - condition: template
    value_template: >
      {% set media_devices =
        {
        'PowerOff': 'poweroff',
        'Televisie': 'television',
        'Mediaplayer': 'mediaplayer',
        'Apple-TV': 'appletv',
        'Radio':, 'radio',
        'Muziek': 'music',
        'DVD': 'dvd',
        'Teletekst': 'teletext',
        'Smart-TV': 'smarttv'
        }
      %}
      {{ old_state in media_devices.keys() }}
  - service: input_boolean.turn_off
    data_template:
      entity_id: >
        {% set media_devices =
        {
          'PowerOff': 'poweroff',
          'Televisie': 'television',
          'Mediaplayer': 'mediaplayer',
          'Apple-TV': 'appletv',
          'Radio':, 'radio',
          'Muziek': 'music',
          'DVD': 'dvd',
          'Teletekst': 'teletext',
          'Smart-TV': 'smarttv'
        }
        %}
      input_boolean.{{ media_devices[old_state] }}

So, it appears as if you are trying to use toggles to switch your harmony activities. There’s a much better way to do this without scripts, switch templates. Check out the switch template section in this post:

Harmony Activities, Volume Slider, and Lovelace

Hello everyone, I’ve been getting quite a few messages about my harmony setup, so I decided to create this post to give it more visibility. I attempted to create a ‘minimalist’ approach to an interface that works identical to the harmony remotes activities. That being, when one activity is turned on, all others are off. This functionality is built into the harmony remote and it can be quite difficult to replicate in the Home Assistant user interface. The second thing to note here is that I a…

Basically the switches will only be on when the activity is on. You don’t have to worry about toggling other input_booleans off when you turn on another activity.

EDIT: I also want to clarify. The reason your template isn’t working is because you are attempting to use a list of tuples to get your information. You need to use a dictionary. Notice the syntax change for media_devices. That is the proper way to make a dictionary in jinja. The way you were writing it was a list of tuples ().