Tax rate for user role

gistfile1.txt

/**
* Apply a different tax rate based on the user role. 
*/
function wc_diff_rate_for_user( $tax_class, $product ) {
    $tax_class = 'zero-rate';
       // Getting the current user
    $current_user = wp_get_current_user();
    $current_user_data = get_userdata($current_user->ID);
    if ( is_user_logged_in() &&
            in_array( 'au_export_trade_45', $current_user_data->roles ) ||
            in_array( 'row_trade_45', $current_user_data->roles ) ||
            in_array( 'row_distributor', $current_user_data->roles ) ||
            in_array( 'eu_ext_trade_45', $current_user_data->roles ) ||
            in_array( 'us_distributor_50', $current_user_data->roles ) ||
            in_array( 'us_trade_40', $current_user_data->roles )) {
        $tax_class = 'Zero Rate';
    }

    return $tax_class;
}
add_filter( 'woocommerce_product_get_tax_class', 'wc_diff_rate_for_user', 1, 2 );