I'm encountering an error in helpdesk.ticket when calling a custom method within a scheduled action

Question

This is my scheduled action in Odoo:
action image

and this is my code:

# -*- coding: utf-8 -*-
from odoo import models, api
import pika
import json
import logging
_logger = logging.getLogger(__name__)
class HelpdeskTicket(models.Model):
 _inherit = 'helpdesk.ticket'
 def send_stage_change_to_rabbitmq(self):
 _logger.info("Méthode OK : chargée dans helpdesk.ticket")

I encountered an error in the container logs:
error image

• CZoellner: Probably a stupid question, but: Are you sure your module is installed and every __init__.py is filled correctly?
• agilgur5: Please do not upload images of code/data/errors.
• karim: yes, the module is installed correctly and the init also
• CZoellner: With all the information available, I cannot see any mistake.
• karim: I'm using helpdesk_mgmt.model_helpdesk_ticket instead of helpdesk.ticket in the action, and it's working.