i'm using odoo 9 and i want to modify the action on the button print in invoices .So i have created a custom module to override  the function invoice_print to satisfy my conditions but i notice that only the button print in the workflow bar ha been changed ,the other button print which is next to the button Action doesn't apply the modification. I have spend many hours to search the function of this button but i don't know where is the function of this button any help please ?? 

https://ibb.co/BfFDrVY

here is the function that i have modified :

 @api.multi
def invoice_print(self):
 if (self.partner_id.CodeTVA == False) or (self.partner_id.street == False):
        raise UserError(
            _("vous ne pouvez pas lancer l impression. Veuillez remplir le code TVA et/ou l'adresse du partenaire" ))

    elif (self.partner_id.CodeTVA == True) and (self.partner_id.street == True):
        self.ensure_one()
        self.sent = True
    # return self.env['report'].get_action(self, 'account.report_invoice')
    return self.env['report'].get_action(self, 'bi_professional_reports_templates.report_invoice')