Hi,

To enable stage folding in a Kanban view, you need to add the attribute group_expand to the stage_id field in your model(res.partner).

Python

from odoo import fields, models


class ResPartner(models.Model):
    _inherit = 'res.partner'

    stage_id = fields.Many2one('contacts.stage', string='Status',
                               group_expand='_read_group_expand_full')

Hope it helps

got the answer

@api.model
def _read_group_stage_ids(self, stages, domain):
search_domain = [('id', 'in', stages.ids)]
stage_ids = stages.sudo()._search(search_domain, order=stages._order)
return stages.browse(stage_ids)

or if your all stage invisible then try below code

@api.model
def _read_group_stage_ids(self, stages, domain):
stage_ids = self.env['contacts.stage'].search([])
return stage_ids