odoo controller inheritance

sale_checkout_inheritance.py

from odoo.addons.website_sale.controllers.main import WebsiteSale

class WebsiteSaleInherit(WebsiteSale):
    @http.route(['/shop/checkout'], type='http', auth="public", website=True)
    def checkout(self, **post):
        # use super to call prevously defined checkout methods so we not overriding the method but extend it.
        res = super(WebsiteSale, self).checkout(**post)   
        # code your bugs in here ;)

have a look into: http://learnopenerp.blogspot.com/2020/08/inherit-web-login-controller-in-odoo.html