WC_Email_Customer_Invoice::get_subject PHP Метод

        public function get_subject()
        {
            if ($this->object->has_status(wc_get_is_paid_statuses())) {
                return apply_filters('woocommerce_email_subject_customer_invoice_paid', $this->format_string($this->subject_paid), $this->object);
            } else {
                return apply_filters('woocommerce_email_subject_customer_invoice', $this->format_string($this->subject), $this->object);
            }
        }

 /**
  * get_subject function.
  *
  * @access public
  * @return string
  */
 function get_subject()
 {
     return apply_filters('woocommerce_subscriptions_email_subject_new_renewal_order', parent::get_subject(), $this->object);
 }