Deprecated function contextual_help()

I am getting the following notice at the top of the admin pages:

Deprecated: contextual_help is deprecated since version 3.3.0! Use get_current_screen()->add_help_tab(), get_current_screen()->remove_help_tab() instead. in /wp-includes/functions.php on line 5234

I found two instances of contextual_help in MailchimpCampaignsManager MailchimpAdmin.php

    public function __construct() {
      parent::__construct();
      add_action('contextual_help', array($this, 'help_tab'), 10, 3);
      add_action('admin_menu', array($this, 'add_plugin_page'));
      add_action('admin_init', array($this, 'admin_init'));

public function help_tab($contextual_help, $screen_id, $screen) {
      if ($this->post_type == $screen->id || $screen_id == 'settings_page_mailchimp_campaigns_manager-admin') {
        $screen = get_current_screen();
        $screen->add_help_tab(array(
          'id'      => $screen->id,
          'title'   => __('Help'),
          'content' => __('You can import your mailchimp campaigns from the settings page (Settings > Mailchimp Campaign).', MCC_TEXT_DOMAIN),
        ));
      }
    }