Lees ook deze reeksen over literatuur

		WP_Hook Object
(
    [callbacks] => Array
        (
            [10] => Array
                (
                    [00000000000029110000000000000000ywgc_custom_cart_product_image] => Array
                        (
                            [function] => Array
                                (
                                    [0] => YITH_YWGC_Cart_Checkout_Premium Object
                                        (
                                        )

                                    [1] => ywgc_custom_cart_product_image
                                )

                            [accepted_args] => 2
                        )

                    [spq_custom_data_cart_thumbnail] => Array
                        (
                            [function] => spq_custom_data_cart_thumbnail
                            [accepted_args] => 4
                        )

                )

        )

    [priorities:protected] => Array
        (
            [0] => 10
        )

    [iterations:WP_Hook:private] => Array
        (
        )

    [current_priority:WP_Hook:private] => Array
        (
        )

    [nesting_level:WP_Hook:private] => 0
    [doing_action:WP_Hook:private] => 
)