Add the user's Display Name to the Members List CSV export

my_pmpro_members_list_csv_display_name_column.php

<?php
/**
 * Add the user's Display Name to the Members List CSV
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */

function my_pmpro_members_list_csv_display_name_column( $columns ) {
	$columns["display_name"] = "my_pmpro_members_list_csv_display_name_column_data";
	return $columns;
}
add_filter( 'pmpro_members_list_csv_extra_columns', 'my_pmpro_members_list_csv_display_name_column' );

function my_pmpro_members_list_csv_display_name_column_data( $user ) {
	return $user->display_name;
}