Add custom post type search in wordpress

functions.php

<?php
add_filter( 'pre_get_posts', 'custom_post_search' );

function custom_post_search( $query ) {
 $post_type = get_query_var('post_type');  
    if ( $query->is_search && !is_admin() ) {
	      $query->set( 'post_type', array( 'post', 'movies', 'products', 'portfolio', 'ai1ec_event' ) );
    }
  else if ( $query->is_search && is_admin() && $post_type == 'ai1ec_event' ){
	    $query->set( 'post_type', array( 'ai1ec_event' ) );
  }
	
    return $query;
}