Exclude certain levels from checkout page

excude_level_from_checkout_page.php

<?php
function pmpro_custom_filter_checkout_levels( $pmpro_level ) {

	// get the current user
	$user = wp_get_current_user();

	// if the user is logged in
	if ( $user->ID ) {

		// get the user's membership level
		$level = pmpro_getMembershipLevelForUser( $user->ID );

		// if the user has a membership level 1
		if ( $level->id == 1 ) {
				// remove the level from the array
				unset( $pmpro_level[3] );
		}

	}

	return $pmpro_level;
}


add_filter( 'pmpro_levels_array', 'pmpro_custom_filter_checkout_levels' );