public function isEmpty()
    {
        return empty($this->subject)
            || (empty($this->customMessage) && empty($this->paymentMessage) && empty($this->shipmentMessage));
    }
public function isEmpty()
    {
        return empty($this->subject)
            || (empty($this->customMessage) && empty($this->paymentMessage) && empty($this->shipmentMessage));
    }
Returns whether there is no defined message.

@return bool