[WooCommerce 3.0+] Re-instate the "Purchased items" column on orders page

wc-custom-purchased-column.php

<?php
/** Add a Purchased Column w/ Item Quantity, SKU, Name, & Meta to the Admin Orders Table **/
class ThemeWooCommerce
{
  /* Add a `Purchased` Column to the Admin Orders Table */
  public static function add_purchased_column_header($columns) {
    $new_columns = array();
    foreach ($columns as $key => $title) {
      if ($key === 'billing_address') {
        $new_columns['order_items'] = __('Purchased', 'woocommerce');
      }
      $new_columns[$key] = $title;
    }
    return $new_columns;
  }

  /* Render the `Purchased` Column in the Admin Orders Table */
  public static function render_purchased_column($column) {
    global $the_order;
    if ($column === 'order_items') {
      $item_count = $the_order->get_item_count();
      $item_count_text =
        apply_filters(
          'woocommerce_admin_order_item_count',
          sprintf(_n('%d item', '%d items', $item_count, 'woocommerce'), $item_count),
          $the_order
        );
      echo "<a href='#' class='show_order_items'>{$item_count_text}</a>";
      $order_items = $the_order->get_items();
      if (sizeof($order_items) > 0) {
        echo "<table class='order_items' cellspacing='0'>";
        foreach ($order_items as $item) {
          $product = apply_filters(
            'woocommerce_order_item_product', $item->get_product(), $item);
          $item_meta = new WC_Order_Item_Meta($item, $product);
          $item_meta_html = $item_meta->display(true, true);
          $item_class = apply_filters(
            'woocommerce_admin_order_item_class', '', $item, $the_order);
          $item_name = apply_filters(
            'woocommerce_order_item_name', $item->get_name(), $item, false);
          echo "<tr class='{$item_class}'>" .
            "<td class='qty'>" . esc_html($item->get_quantity()) . "</td>" .
            "<td class='name'>";
          if ($product) {
            $sku = $product->get_sku();
            $edit_link = get_edit_post_link($product->get_id());
            if (wc_product_sku_enabled() && $sku !== '') { echo "{$sku} - "; }
            echo "<a href='{$edit_link}'>{$item_name}</a>";
          } else {
            echo $item_name;
          }
          if (!empty($item_meta_html)) {
            echo wc_help_tip($item_meta_html);
          }
          echo "</td>";
        }
        echo "</table>";
      }
    }
  }
}

add_filter('manage_edit-shop_order_columns', array('ThemeWooCommerce', 'add_purchased_column_header'));
add_action('manage_shop_order_posts_custom_column', array('ThemeWooCommerce', 'render_purchased_column'));

?>