Salesforecast(first model) is the master class and salesforecastproducts model holds the products list and salesforecast.products.itemlines holds the bom list. but when i add a product in the table it was supposed to fill the next page of the notebook it's not. The problem i guess is on the onChange Thanks for the help

from odoo import fields, models,api


class Salesforecast(models.Model):
    """ Manufacturing Orders """
    _name = 'mrp.salesforecast'
    _description = 'Salesforecast model'
   salesforecast_name = fields.Char(
        'Salesforecast ref')
    
    salesforecast_product = fields.One2many('mrp.salesforecastproducts', 'salesforecast_id', 'Salesforecast Products')
    salesforecast_items = fields.One2many(related='salesforecast_product.salesforecast_product_items_id',string="Ingredients",store=True, required=True)


class SalesforecastProducts(models.Model):
    """ Manufacturing Orders """
    _name = 'mrp.salesforecastproducts'
    _description = 'Salesforecast Products'

    

    @api.onchange('product_qty','bom_id')
    def onchange_product_id(self):
        """ Finds UoM of changed product. """
        for rec in self:
            if self.bom_id and rec.product_qty > 0:
                bom = self.env['mrp.bom']._bom_find(product=rec.product_id,
                                                    bom_type='normal')
                list_bom_items = []
                for bo in bom:
                     obje = {
                        'item_id': bo.product_id.id,
                        'product_id': rec.product_id.id,
                        'item_qty': bo.product_qty ,
                        'item_available': bo.product_id.qty_available,
                        'item_required': 1}
                     list_bom_items.append((0, 0, obje))
                rec.salesforecast_product_items_id = list_bom_items

    salesforecast_id = fields.Many2one(
        'mrp.salesforecast', 'Salesforecast', store=True)
    product_id = fields.Many2one(
        'product.product', 'Product Name', store=True)
    salesforecast_product_items_id = fields.One2many('mrp.salesforecastproductsitems', 'salesforcast_product_id',
                                                     string="Items List")
    product_qty = fields.Float(
        'Quantity Forecasted',
        default=1.0, digits='Product Unit of Measure',
        readonly=False, required=True)
    product_batch_size = fields.Float(
        'Batch Size',
        default=1.0, digits='Product Unit of Measure',
        required=True)
    bom_id = fields.Many2one(
        'mrp.bom', 'Bill of Material',
        domain="""[
                ('product_id','=',product_id),
                    '&',
                        ('product_tmpl_id.product_variant_ids','=',product_id),
                        ('product_id','=',False),
        ('type', '=', 'normal')]""",
        check_company=True, store=True)




class SalesforecastProductsItems(models.Model):
    """ salesforecast ingredients """
    _name = 'mrp.salesforecastproductsitems'
    _description = 'Salesforecast BOM Items'

    salesforcast_product_id = fields.Many2one('mrp.salesforecastproducts', 'salesforecast product ref')
    item_id = fields.Many2one(
        'product.product', 'Item Name')
    product_id = fields.Many2one(
        'product.product', 'Product')
    item_qty = fields.Float(
        'Required Quantity',
        default=1.0)

    item_available = fields.Float(
        'Qty available',
        related='item_id.qty_available',
        readonly=False, store=True)

    item_required = fields.Float(
        'Item required')