So i have this field, basically, it computes the subtotal of the product using the unit price and quantity:

 pr_subtotal = fields.Float(

        string="Subtotal",

        compute='_compute_subtotal',

        store=True

   )

And here is the compute function:

@api.onchange('qty', 'unit_price')

def _compute_subtotal(self):

     for record in self:

            record.pr_subtotal = record.qty * record.unit_price

However, when i am saving it keeps reseting to 0. Am i missing something?