adding bcc to reminder emails

functions.php

<?php

function bkap_booking_reminder_add_cc_bcc( $headers, $email_id, $order ) {
    if ( 'bkap_booking_reminder' == $email_id ) {
        $admin_email = get_option( 'admin_email' );
        $headers .= "Bcc: Admin <" . $admin_email . ">\r\n";
    }
    return $headers;
}
add_filter( 'woocommerce_email_headers', 'bkap_booking_reminder_add_cc_bcc', 9999, 3 );