I have a new module called new_leaves as I made some changes in hr.holidays module 
I have to approves one for the manager of the department and the other for leaves manager( I created a new user and I set his sittings as manager of leaves and an officer in employee category) , I want that the leaves manager receives a notification after manager approve for an employee leave I updated this function in my new module but it does not work , any help? 

class new_leaves(models.Model):
    _inherit = 'hr.holidays'
    state = fields.Selection([
        ('draft', 'To Submit'),
        ('cancel', 'Cancelled'),
        ('confirm', 'To Approve'),
        ('manager', 'Manager Approve'),
        ('hr_approve','HR Approve'),
        ('refuse', 'Refused'),
        ('validate1', 'Second Approval'),
        ('validate', 'Approved')
        ], string='Status', readonly=True, track_visibility='onchange', copy=False, default='confirm',
            help="The status is set to 'To Submit', when a holiday request is created." +
            "\nThe status is 'To Approve', when holiday request is confirmed by user." +
            "\nThe status is 'Refused', when holiday request is refused by manager." +
            "\nThe status is 'Approved', when holiday request is approved by manager.")

@api.multi
def _notification_recipients(self, message, groups):
    """ Handle HR users and officers recipients that can validate or refuse holidays
    directly from email. """
    groups = super(new_leaves, self)._notification_recipients(message, groups)

    self.ensure_one()
    hr_actions = []
    if self.state == 'manager':
        app_action = self._notification_link_helper('controller', controller='/new_leaves/hr_approve')
        hr_actions += [{'url': app_action, 'title': _('Approve')}]
    if self.state in ['confirm', 'validate', 'validate1','manager','hr_approve']:
        ref_action = self._notification_link_helper('controller', controller='/new_leaves/refuse')
        hr_actions += [{'url': ref_action, 'title': _('Refuse')}]

    new_group = (
        'group_hr_holidays_manager', lambda partner: bool(partner.user_ids) and any(user.has_group('hr_holidays.group_hr_holidays_manager') for user in partner.user_ids), {
            'actions': hr_actions,
        })

    return [new_group] + groups

and in controller file :

from odoo.addons.mail.controllers.main import MailController
from odoo import http

class Ra(http.Controller):

    @http.route('/new_leaves/manager', type='http', auth='user', methods=['GET'])
    def hr_holidays_validate(self, res_id, token):
        comparison, record, redirect = MailController._check_token_and_record_or_redirect('hr.holidays', int(res_id), token)
        if comparison and record:
            try:
                record.action_approve()
            except Exception:
                return MailController._redirect_to_messaging()
        return redirect

    @http.route('/new_leaves/refuse', type='http', auth='user', methods=['GET'])
    def hr_holidays_refuse(self, res_id, token):
        comparison, record, redirect = MailController._check_token_and_record_or_redirect('hr.holidays', int(res_id), token)
        if comparison and record:
            try:
                record.action_refuse()
            except Exception:
                return MailController._redirect_to_messaging()
        return redirect

​