Add Custom Message to WordPress Login Page

/*
  Add custom message to WordPress login page
*/
function SVS_login_message( $message ) {
  if ( empty($message) ){
    return "<p><strong>This login is only for Site Admins. If you are something else, please click the logo above and use the LOGIN link in the main menu.</strong></p>";
  } else {
    return $message;
  }
}
add_filter( 'login_message', 'SVS_login_message' );