Variable in Package

Configuration
1

Hi everyone,
I am new to home assistant and am still taking my first steps.

I wanted to ask something:
I have a package file e.g. shelly_camera.yaml where I have configured all the shelly parameters.

###SHELLY TEST .10
switch:
  - platform: mqtt
    name: "Shelly Test ON/OFF"
    state_topic: "shellies/shelly1pm-test/relay/0"
    command_topic: "shellies/shelly1pm-test/relay/0/command"
    availability_topic: "shellies/shelly1pm-test/online"
    qos: 2
    value_template: "{% if value == 'on' %} on {% else %} off {% endif %}" 
    payload_on: "on"
    payload_off: "off"
    payload_available: "true"
    payload_not_available: "false"
    optimistic: false
    retain: false

I would like to create a variable for the id (shelly1pm-test) of the shelly so if I have to modify it I don’t have to change it everywhere.

EDIT:

I have tried like this but dont working:

variables:
 nome_shelly: "shelly1pm-test"
 
 ...
 
 state_topic: "shellies/{{nome_shelly}}/relay/0"
2

What you want is not possible, take a look here for a semi-viable option