Hi,

You can achieve this by using BeautifulSoup python library to check if the activity was ticked or not inside the html field of activity.
If it is ticked, the class will be changed to "o_checked".
We can then change the boolean field "Vegetarian" to true or false based on this.
Kindly refer the code,

from odoo import api, fields, models, _from bs4 import BeautifulSoup​
class HrEmployee(models.Model):
    
    _inherit = 'hr.employee'
    vegetarian = fields.Boolean("Vegetarian", default=False, readonly=True)


class HrPlanActivityType(models.Model):
    _inherit = 'mail.activity'
    def action_close_dialog(self):
        """
        function used to check if the employee can be
        rehire by the checkbox
        """
    res = super(HrPlanActivityType, self).action_close_dialog()
    employee_id = self.env['hr.employee'].search([('id', '=', self._context['default_res_id'])])
    for line in employee_id.activity_ids:
        if line.note:
        soup = BeautifulSoup(line.note, 'html.parser')
    if soup.find(id="checklist-re_hide-id-4", class_="o_checked"):
        employee_id.write({"vegetarian": True})
    else:
        employee_id.write({"vegetarian": False})
    return res
Regards