How to call a function or method that is Namespaced using another plugin

  echo $plugins_dir_path = plugin_dir_path( __DIR__ );

echo '<br>';

$mpath = $plugins_dir_path.'woo-mailchimp-newsletter-discount-extended/woocommerce-mailchimp-newsletter-discount.php';

require($mpath);

echo WCMND_PRO_PLUGIN_VERSION;