Sorry if I ask a lot, I do not want to abuse of the forum, but these things do not match. My goal is to create a simple manual in Spanish for Odoo and I need learn and know more, I'm verry happy.

My classes and code in this image (it is dropbox): https://db.tt/aabAZRzb

@api.onchange('producto_id')
    def _onchange_producto_id(self):
        if self.producto_id:
            self.precio = 100.00

Had seen before a self.pool.get used, how can I use it?