Customize woocommerce product gallery without plugin

The original gallery execution function comes from here

wp-content/plugins/woocommerce/includes/class-wc-frontend-scripts.php

$params = array(
    'i18n_required_rating_text' => esc_attr__( 'Please select a rating', 'woocommerce' ),
    'review_rating_required'    => get_option( 'woocommerce_review_rating_required' ),
    'flexslider'                => apply_filters(
        'woocommerce_single_product_carousel_options', array(
            'rtl'            => is_rtl(),
            'animation'      => 'slide',
            'smoothHeight'   => true,
            'directionNav'   => false,
            'controlNav'     => 'thumbnails',
            'slideshow'      => false,
            'animationSpeed' => 500,
            'animationLoop'  => true, // Breaks photoswipe pagination if true.
            'allowOneSlide'  => false,
        )
    ),
);

So we can use a filter and put it to functions.php of the active theme as like

add_filter( 'woocommerce_single_product_carousel_options', 'customslug_single_product_carousel_options', 99, 1 );
function customslug_single_product_carousel_options( $options ) {
    $options['animation'] = 'fade';
    $options['animationSpeed'] = 400;
    $options['directionNav'] = true;
    return $options;
}