Add class to wordpress post in loop

function hs_post_classes( $classes, $class, $post_id ) {
 
	if( is_single() ) {
		$classes[] .= 'hs-single-post';
	} else if ( is_page() ) {
		$classes[] .= 'hs-page';	
	} else {
		$classes[] .= 'main-post';
	}
     
    return $classes;
}

add_filter( 'post_class', 'hs_post_classes', 10, 3 );