WPMU Membership assign membership based on role on registration

code.php

<?php

add_action( 'user_register', 'assign_membership_on_register', 10, 1 );
function assign_membership_on_register( $user_id ) {
    
    $membership = array(
        // 'role' => 'membership ID'
        'abc' => 123,
        'xyz' => 456
    );
    
    $user_meta = get_userdata( $user_id );
    $user_roles = $user_meta->roles;
    
    $member = MS_Factory::load( 'MS_Model_Member', $user_id );
    $subscription = $member->add_membership( $membership[ $user_roles[0] ] );

    if ( $member->has_membership() ) {
        $member->is_member = true;
    } else {
        $member->is_member = false;
    }
    $member->save();
}