I'm trying to add a custom button open whatsapp in res.partner form. But everytime i clicked the button nothing happened.

here is my record and model :

class ResPartner(models.Model):

_inherit = 'res.partner'

def wa_btn(self):

if self.mobile:

return
{

'type': 'ir.actions.act_url',
'name': 'Coba Whatsapp',
'url': "https://api.whatsapp.com/send?phone=" + self.mobile + "&text=Test_Whatsapp",
'target': 'new',
'context': self._context,
}

else:

return UserError(_("Error Chat WA"))

Sorry, about image code,

I don't know what went wrong.