It not working for me!

woocommerce 2.6.3
i installed wp city select then i added this code at the end of functions.php in my theme.

in what I did wrong

Thank you very much

add_filter( 'wc_city_select_cities', 'my_cities' );

function my_cities( $cities ) {
  $cities['NG'] = array(
    'LA' => array(
        'Ikorodu',
        'Ikeja'
    ),
    'OY' => array(
        'Ibadan',
        'Saki'
    )
  );
  return $cities;
}