WC_Email_Customer_Completed_Order::get_heading PHP Method

        public function get_heading()
        {
            if (!empty($this->object) && $this->object->has_downloadable_item()) {
                return apply_filters('woocommerce_email_heading_customer_completed_order', $this->format_string($this->heading_downloadable), $this->object);
            } else {
                return apply_filters('woocommerce_email_heading_customer_completed_order', $this->format_string($this->heading), $this->object);
            }
        }

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