Passing media player to script

I have a script that I am using for morning announcements. I am able to pass the media device, the person’s name, and whether or not a morning briefing is needed. The issue I’m having is when I pass the media device, this works:

service: notify.alexa_media
data:
  message: >
    <voice name="Brian"> <amazon:auto-breaths> <prosody rate="fast"> {%from
    'phrases.jinja' import goodmorning_phrases %} {{ goodmorning_phrases |
    random }} <emphasis level="moderate"> {{ target_name }} </emphasis> <break/>
    Time to get <emphasis level="moderate"> up </emphasis> </prosody>
    </amazon:auto-breaths> </voice>
  target: media_player.{{ speaker_target }}
  data:
    type: tts
enabled: true

However this does not:

service: notify.alexa_media
data:
  message: >
    <voice name="Brian"> <amazon:auto-breaths> <prosody rate="fast"> {%from
    'phrases.jinja' import goodmorning_phrases %} {{ goodmorning_phrases |
    random }} <emphasis level="moderate"> {{ target_name }} </emphasis> <break/>
    Time to get <emphasis level="moderate"> up </emphasis> </prosody>
    </amazon:auto-breaths> </voice>
  target: 
    - '{{ speaker_target }}'
  data:
    type: tts
enabled: true

This is the automation I’m using to call the script:

service: script.morning_announcement_and_briefing
data:
  target_name: Erik
  briefing_needed: "True"
  speaker_target: office_echo

when I’m trying to pass the entity ID in the example that doesn’t work, I am passing media_player.office_echo.

I’m obviously missing something here but can’t find it. Long term I’d like to pass multiple entities to this announcement, is that possible?

The second target entity has no domain.

When I pass it in I’m passing it in as media_player.office_echo. This suddenly seems to work.

service: script.morning_announcement_and_briefing
data:
  target_name: Erik
  briefing_needed: "True"
  speaker_target: media_player.office_echo

The question I now have is, should I add the - in front of that to be consistent and can I pass multiple media players that way? I’ve not been able to get it to work if i pass it like this:

service: script.morning_announcement_and_briefing
data:
  target_name: Erik
  briefing_needed: "True"
  speaker_target: - media_player.office_echo

I figured it out. My sytax was wrong. I changed it to this and it works now. Thanks for the help!

service: script.morning_announcement_and_briefing
data:
  target_name: Erik
  briefing_needed: "True"
  speaker_target:
    - media_player.office_echo
    - media_player.master_bedroom_echo