app\models\Invoice::markInvitationsSent PHP Method

    public function markInvitationsSent($notify = false)
    {
        foreach ($this->invitations as $invitation) {
            $this->markInvitationSent($invitation, false, $notify);
        }
    }

 /**
  * @param Invoice $invoice
  */
 public function markSent(Invoice $invoice)
 {
     $invoice->markInvitationsSent();
 }