Add suffix price through tax name with slug

Add suffix price through tax name with slug.php

<?

/*
 * 	Add suffix price through tax name with slug
 */

add_filter( 'woocommerce_available_variation', 'custom_variation_price', 10, 3 );
function custom_variation_price( $data, $product, $variation ) {
    $price_excl_tax = (float) wc_get_price_excluding_tax( $variation ); // price without VAT
    $price_incl_tax = (float) wc_get_price_including_tax( $variation );  // price with VAT
    $tax_amount     = $price_incl_tax - $price_excl_tax;

    if( $variation->get_tax_class() === 'nessuna-tariffa' ) {
        $data['price_html'] = wc_price($price_excl_tax) . __(' IVA INCLUSA');
    }else{
		$data['price_html'] = wc_price($price_excl_tax) . __(' IVA ESCLUSA');
	}
    return $data;
}