WooCommerce - Change a currency symbol

// WooCommerce - Change a currency symbol
add_filter( 'woocommerce_currency_symbol', 'change_existing_currency_symbol', 10, 2);
function change_existing_currency_symbol( $currency_symbol, $currency ) {
  switch( $currency ) {
    case 'SEK':
      $currency_symbol = 'SEK';
      break;
  }
  return $currency_symbol;
}