Adding a productAttribute handler in Magento 2

di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">

    <type name="Magento\Catalog\Helper\Output">
        <plugin name="OutputHelper" type="Vendor\Module\Plugin\OutputPlugin" sortOrder="1"/>
    </type>
  
</config>

OutputPlugin.php

<?php

namespace Vendor\Module\Plugin;

use Magento\Catalog\Helper\Output;

class OutputPlugin {

	// this plugin method should be on a method which collects all handlers and isn't called everytime the handlers are processed
	public function beforeProcess(Output $outputHelper, $method, $result, $params) {
		$handlers=$outputHelper->getHandlers('productAttribute'); 
		if(!in_array($this,$handlers)){
			$outputHelper->addHandler('productAttribute', $this);
		}
		return [$method, $result, $params];
	}

	public function productAttribute($helper, $value, $parameters) {
		$attribute = $parameters['attribute'];
		switch ($attribute) {
			case 'attribute' :
				$r = '<ul class="advice">' . implode("\n", $attribute) . '</ul>';
				break;
			default:
				$r = $value;
				break;
		}
		return $r;
	}
}