Woocommerce Currenncy Prefix

madd_filter('woocommerce_currency_symbol', 'alter_currency_symbol', 10, 2);
function alter_currency_symbol( $currency_symbol, $currency ) {
switch( $currency ) {
case 'AUD': $custom_currency_symbol = 'AUD$'; break;
}
return $custom_currency_symbol;
}