WC_Gateway_Paypal::log PHP Method

    public static function log($message)
    {
        if (self::$log_enabled) {
            if (empty(self::$log)) {
                self::$log = wc_get_logger();
            }
            self::$log->add('paypal', $message);
        }
    }

 /**
  * Find all subscription with a given billing agreement ID and cancel them becasue that billing agreement has been
  * cancelled at PayPal, and therefore, no future payments can be charged.
  *
  * @since 2.0
  */
 protected function cancel_subscriptions($billing_agreement_id)
 {
     $subscription_ids = get_posts(array('posts_per_page' => -1, 'post_type' => 'shop_subscription', 'post_status' => 'any', 'fields' => 'ids', 'orderby' => 'date', 'order' => 'DESC', 'meta_query' => array(array('key' => '_paypal_subscription_id', 'compare' => '=', 'value' => $billing_agreement_id))));
     if (empty($subscription_ids)) {
         return;
     }
     $note = esc_html__('Billing agreement cancelled at PayPal.', 'woocommerce-subscriptions');
     foreach ($subscription_ids as $subscription_id) {
         $subscription = wcs_get_subscription($subscription_id);
         try {
             if (false !== $subscription && !$subscription->has_status(wcs_get_subscription_ended_statuses())) {
                 $subscription->cancel_order($note);
                 WC_Gateway_Paypal::log(sprintf('Subscription %s Cancelled: %s', $subscription_id, $note));
             }
         } catch (Exception $e) {
             WC_Gateway_Paypal::log(sprintf('Unable to cancel subscription %s: %s', $subscription_id, $e->getMessage()));
         }
     }
 }