How to template a command for setting an effect on a MQTT light

Configuration
1

Hello,

if I have a mqtt light with

effect_list:
 - "effect 1"
 - "effect 2"
 - "effect 3"

And the device accepts this MQTT command, on “/some/topic”, for enabling an effect:

EFFECT=n

(Where n is a number between 1 and 3)

Given that, which strings do I have to set for:

effect_command_topic: …
effect_value_template: …

… in order to send the previous command to the device, on the previous topic?

Thanks