theme class instance

sample.php

<?php
function om_sample_lightbox_theme_api( $api, $theme, $optin_id, $type ) {

	// Let's make sure we're adding to the lightbox themes. If not, return early.
	if ( 'lightbox' != $type ) {
		return $api;
	}

	// Also return if we're not using the Sample theme
	if ( 'sample' != $theme ) {
		return $api;
	}

	// Require the theme file
	if ( ! class_exists( 'Optin_Monster_Lightbox_Theme_Sample' ) ) {
		require plugin_dir_path( __FILE__ ) . 'lightbox-sample.php';
	}
	$api = new Optin_Monster_Lightbox_Theme_Sample( $optin_id );

	return $api;

}