Hello I have the following class :

class BonDeCommande(models.Model):
    _inherit = 'purchase.order'

    history = fields.Many2one('app.purch.order.line', string='Historique')

    # Overwrite from onchange partner method
    @api.onchange('partner_id', 'company_id')
    def onchange_partner_id(self):
        if not self.partner_id:
            self.fiscal_position_id = False
            self.payment_term_id = False
            self.currency_id = False
        else:
            self.fiscal_position_id = self.env['account.fiscal.position'].with_context(
                company_id=self.company_id.id).get_fiscal_position(self.partner_id.id)
            self.payment_term_id = self.partner_id.property_supplier_payment_term_id.id
            self.currency_id = self.partner_id.property_purchase_currency_id.id or self.env.user.company_id.currency_id.id

             # Link properties between tables
            for i in self.env['app.catalogue.liste.catalogue'].search([('supplier', '=', self.partner_id.id)]):

                # Create an array of object for different lines
                lines = []
                for line in i.liste_id:
                    # get values and converte date
                    good_date = fields.Date.from_string(self.date_order)
                    get_date = (good_date + datetime.timedelta(hours=2)).strftime("%x")

                    hist = dict()
                    for j in self.env['purchase.order.line'].search([('product_id', '=', line.product.id)]):
                        hist[j.date_order] = j.product_qty
                    print hist

                    new_line = {
                        'order_id': False,
                        'product_id': line.product.id,
                        'name': line.product.name,
                        'product_qty': line.quantity,
                        'date_planned': i.date_to,
                        'product_uom': 1,
                        'price_unit': line.price,
                        'history': hist
                    }
                    lines.append((0, 0, new_line))
                    # print lines

                # Check if the lines exists
                if not self.order_line:
                    print 'vider ...... \n'
                    self.order_line = lines
                else:
                    print 'remplir .... \n'
                    self.order_line = lines

        return {}

And :

class PurchOrderLine(models.Model):
    _inherit = 'purchase.order.line'
    _rec_name = 'history'
    history = fields.Char(string='Historique')

The result I get in my history field is this one :

{'2020-10-16 12:21:46': 9.0, '2020-10-14 13:21:56': 6.0}

Which is correct, but it display it as a Char.... So I suppose I must reverse my fields. But the problem is if I did it my Many2one is through purchase.order and I get all the fields and not only my history one as i expect.

Do you have any ideas how I could display the dict object in a correct way for a selection.

Thx