How do I create a computed field on an invoice in Odoo 11 using Python?

Our company pays commissions based on the discount given on a line by line basis. I am trying to show this commission amount on the invoice copy we send to the sales rep.

I am using Odoo studio in v12.0 and created a field x_studio_field_dakHb labeled "Commission Amount" that appears in account.invoice.line model.

I have checked the "Readonly" and "Stored" boxes. In "Dependencies" field I have "discount, price_subtotal".

In the "Advanced Properties" section I have:

def compute_commission_amount(self):
  for record in self:
    if (discount >= 55.0):
      x_studio_field_dakHb = (price_subtotal * .05)
    elif (discount >= 45.0):
      x_studio_field_dakHb = (price_subtotal * .10)
    elif (discount >= 30.0):
      x_studio_field_dakHb = (price_subtotal * .15)
    elif (discount >= 25.0):
      x_studio_field_dakHb = (price_subtotal * .20)
    elif (discount >= 0.0):
      x_studio_field_dakHb = (price_subtotal * .25)

I am not getting any errors, but the field is not not calculating as I anticipated.

An example of what I am expecting would be as follows:

Invoice Table

Is there something I am missing in my code to get it to calculate properly?

Solution

You have to use record to assign your values. On a field you will find following hint on compute methods:

The field Compute is the Python code to compute the value of the field on a set of records. The value of the field must be assigned to each record with a dictionary-like assignment.
for record in self:
    record['size'] = len(record.name)

So your code should be like:

def compute_commission_amount(self):
    for record in self:
        if (record.discount >= 55.0):
            record['x_studio_field_dakHb'] = (record.price_subtotal * .05)
        elif (record.discount >= 45.0):
            record['x_studio_field_dakHb'] = (record.price_subtotal * .10)
        elif (record.discount >= 30.0):
            record['x_studio_field_dakHb'] = (record.price_subtotal * .15)
        elif (record.discount >= 25.0):
            record['x_studio_field_dakHb'] = (record.price_subtotal * .20)
        elif (record.discount >= 0.0):
            record['x_studio_field_dakHb'] = (record.price_subtotal * .25)

Edit: and there was another mistake for price_subtotal which should be get from record. Edit2: and the same with discount