Wordpress Custom Logo Payment Gateway

function cod_gateway_icon( $gateways ) {
    if ( isset( $gateways['cheque'] ) ) {
        $gateways['cheque']->icon = get_stylesheet_directory_uri() . '/images/mb.png';
    }

    return $gateways;
}

add_filter( 'woocommerce_available_payment_gateways', 'cod_gateway_icon' );