How to override an action in a package

ESPHome
1

There is a default voice assistant firmware for my M5Stack atom echo that I overwrite, so that responses can come through my google home mini rather than the terrible speaker on the echo.

In short I am looking to overwrite the package on_timer_finished: with my own

voice_assistant:
  on_timer_finished:

More info

I am using this official esphome firmware package and I overwrite certain elements

For example this does a great job of disabling the speaker

speaker:
  - platform: i2s_audio
    id: !extend echo_speaker
    i2s_dout_pin: GPIO21 # <- It is actually on 22, so this disables the speaker by overriding the package config

and this does a great job of causing the reply to replay on a seperate media_player because on_tts_end: is not specified in the original package.

voice_assistant:
  on_tts_end:
     - homeassistant.service: ...

However when I add the below I find that the existing on_timer_finished: and this one become merged into a single list which produces a terrible result

voice_assistant:
  on_timer_finished:
    - voice_assistant.stop:
    - switch.turn_on: timer_ringing
   ...

And when I try the below I get an error Source for extension of ID 'va' was not found., I think because !extend only works for lists and not dictionaries and voice_assistant is a dictionary

voice_assistant:
  id: !extend va
  ...
My full yaml 
substitutions:
  name: m5stack-atom-echo-b836b0
  friendly_name: M5Stack Atom Echo b836b0
packages:
  m5stack.atom-echo-voice-assistant: github://esphome/firmware/voice-assistant/m5stack-atom-echo.yaml@main
esphome:
  name: ${name}
  name_add_mac_suffix: false
  friendly_name: ${friendly_name}
api:
  encryption:
    key: +myAPIkey=

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

# Until https://github.com/esphome/firmware/pull/233 is fixed/merged
update:
  - platform: http_request
    id: !remove update_http_request

speaker:
  - platform: i2s_audio
    id: !extend echo_speaker
    i2s_dout_pin: GPIO21 # <- It is actually on 22, so this disables the speaker
    dac_type: external
    mode: mono

voice_assistant:
  on_tts_end:
     - homeassistant.service:
         service: media_player.play_media
         data:
           entity_id: media_player.study_speaker # <- this is hard-coded
           media_content_id: !lambda 'return x;'
           media_content_type: music
           announce: "true"    
  on_timer_finished:
    - voice_assistant.stop:
    - switch.turn_on: timer_ringing
    - wait_until:
        not:
          microphone.is_capturing:
    - light.turn_on:
        id: led
        red: 0%
        green: 100%
        blue: 0%
        brightness: 100%
        effect: "Fast Pulse"
    - while:
        condition:
          switch.is_on: timer_ringing
        then:
          - homeassistant.service:
              service: media_player.play_media
              data:
                entity_id: media_player.study_speaker # <- this is hard-coded
                media_content_id: id(timer_finished_wave_file)
                media_content_type: music
                announce: "true"
          - delay: 1s
    - wait_until:
        not:
          speaker.is_playing:
    - light.turn_off: led
    - switch.turn_off: timer_ringing
    - if:
        condition:
          switch.is_on: use_wake_word
        then:
          - voice_assistant.start_continuous:
          - script.execute: reset_led

So how to a override/overwrite on_timer_finished: rather than just appending it?

2

I also just tried something else

  on_timer_finished: !remove
  on_timer_finished:
    - voice_assistant.stop:
    - switch.turn_on: timer_ringing
    - wait_until:
        not:
  ...

Gives a duplicate key error

Duplicate key "on_timer_finished"
  in "/config/m5-stack-atom-echo-lt.yaml", line 39, column 3
NOTE: Previous declaration here:
  in "/config/m5-stack-atom-echo-lt.yaml", line 38, column 3

and

  on_timer_finished: !remove
    - voice_assistant.stop:
    - switch.turn_on: timer_ringing
    - wait_until:
        not:
   ...

just removes both

3

AFAIK in case of dictionary !extend merge them. Probably so far not possible to override.