server-tools/autovacuum_message_attachment/models/base.py

# Copyright (C) 2019 Akretion
# License LGPL-3.0 or later (http://www.gnu.org/licenses/lgpl.html).

from odoo import fields, models


class Base(models.AbstractModel):
    _inherit = "base"

    assigned_attachment_ids = fields.One2many(
        'ir.attachment', 'res_id', string='Assigned Attachments',
        domain=lambda self: [('res_model', '=', self._name)], auto_join=True
    )