Add a placeholder to post title in admin (Wordpress)

functions.php

<?

// Add placeholder text to an office title
function change_placeholder_text_offices($title){
  $screen = get_current_screen();
  if ( $screen->post_type == 'office' ) {
    $title = 'Enter city name here';
  }
  return $title;
}

add_filter( 'enter_title_here', 'change_placeholder_text_offices' );