How to know when you can use templates

Configuration
1

Is there a way to tell when you can use a data template? Like for lights, I’m pretty sure that brightness can accept a template, but not rgb_color. Today I tried to build a scene to load a random playlist into Sqeezeplay. I tried to use a template for media_content_id and it didn’t work. Is trial and error the best way to determine this?

2

Turns out I had an error in my code. I was able to use a template for media_content_id!

But the original question still stands…

This works (I initially had forgotten to quote strings inside the list that the random item was picked from)

 randomonsqueeze:
    alias: Play random playlist on Squeeze
    sequence:
      - service: media_player.play_media
        data: 
          entity_id: media_player.squeezeplay
          media_content_type: PLAYLIST
        data_template:
          media_content_id: >
            {{ ["http://192.168.1.110:9000/plugins/spotifylogi/index.html?action=playall&index=7f8a835b.7.6&player=bc%3A5f%3Af4%3Ae9%3A44%3A4a&sess=&start=&_dc=1475422566117", "http://192.168.1.110:9000/plugins/spotifylogi/index.html?action=playall&index=7f8a835b.7.0&player=bc%3A5f%3Af4%3Ae9%3A44%3A4a&sess=&start=&_dc=1475422463674"] | random }}

Variations on this have failed:

  weatherlighttest:
    alias: Weather Light Test
    sequence:
      - service: light.turn_on
        entity_id: light.office_rgbw
        data:
          brightness: 255
        data_template:
          rgb_color: >
              {% if states.sensor.forecastio_daily_high_temperature.state | float < 32 %}[168,108,255]{% elif states.sensor.forecastio_daily_high_temperature.state | float < 55 %}[192,255,239]{% elif states.sensor.forecastio_daily_high_temperature.state | float < 80 %}[229,255,193]{% elif states.sensor.forecastio_daily_high_temperature.state | float < 95 %}[255,231,205]{% elif states.sensor.forecastio_daily_high_temperature.state | float < 105 %}[185,13,0]{% else %}[255,255,255]{% endif %}