I've got a button working to print a pdf, how do I write an if condition to chose a pdf that's assigned to my product.product id?

I've got like 13 pdfs for each one, and that button is gonna print one of these according to the product.product id

I only have this function to print one pdf

@api.multi

    def print_work_order(self):

        return self.env['report'].get_action(self, 'orden_trabajo.orden_de_trabajo')