Help with template in color_name

I have this automation which I manually run for testing by clicking on Run actions button.

service: light.turn_on
  entity_id: light.office_backlight
  color_name: '{{ ('red','green','blue')|random }}'
  brightness_pct: 40

Either I get an error while saving it (something like malformed service name or something) but sometimes I can save it and HA removes the template and color_name becomes null. If I change the color_name to say ‘red’ or ‘green’ or ‘blue’, the action works and light changes color.

I am not sure why HA doesn’t like the random filter template in color_name. I have tested the template in developer tools and it returns either red or green or blue randomly. How do I make it work?

I’m quite sure your ( ) should be [ ] around the colors.

No, sorry. It’s the '.
You have the same quote everywhere that won’t work.

'{{ ("red","green","blue")|random }}'

Or the other way around works too:

"{{ ('red','green','blue')|random }}"

Not sure how I missed somethings so basic…

Thank you so much !!!