Add Hours Currency

/** 

 * Add a custom currency called "Hours". 

 *

 * @param   string[] $currencies

 * @return  string[] $currencies

 */ 

function en_add_hours_currency( $currencies ) {

    $currencies[ 'HOURS' ] = __( 'Hours', 'your-namespace' );

    return $currencies;

}

add_filter( 'charitable_currencies', 'en_add_hours_currency' );