Understanding "takes at least X arguments (X given)" error in Odoo

Question

I have the following code in a method of the stock.picking model:

...
for line in picking.move_lines:
    if line.procurement_id and line.procurement_id.sale_line_id:
        sale_line = line.procurement_id.sale_line_id
        _logger.info(sale_line)
        cur = sale_line.order_id.pricelist_id.currency_id
        price = sale_line._calc_line_base_price()
        qty = sale_line._calc_line_quantity()
        ...

I am checking with the logger that sale_line variable is a sale.order.line object -I am getting sale.order.line(14,)-, so I cannot understand why I am getting the following error:

TypeError: _calc_line_base_price() takes at least 4 arguments (4 given)

If I call that method with old API format, it works, but how to call it with new API format?

This answer explains the problem very well, but I think it is not my case as the method I am calling is inside the class of sale.order.line:

Odoo: _get_state() takes at least 4 arguments (4 given) in xml view

Can anyone explain me this? By the way, I am working with version 8.

Answer 1

While calling an old style method within a new style method, Odoo tries to wrap the parameters correctly. Problem here is the method _calc_line_base_price because it can't be wrapped automatically.

def _calc_line_base_price(self, cr, uid, line, context=None):

The parameter line is unsual for this type of methods (call on one instance, new api would be @api.multi with a self.ensure_one()). So you need to call it like a "static" odoo class method:

price = self.env['sale.order.line']._calc_line_base_price(sale_line)