Making .mage('validation' compatible

[pabodah]

Hello,

I have this validation added. How can I convert it to be compatible with Breeze?
At th moment .mage('validation' fails with an error "Uncaught TypeError: $(...).mage is not a function"

    $("#product_addtocart_form").mage("validation", {
        radioCheckboxClosest: ".nested",
        submitHandler: function (form) {
            var widget = $(form).catalogAddToCart({
                bindSubmit: false
            });
            widget.catalogAddToCart("submitForm", $(form));

            return false;
        }
    });

[vovayatsyuk]

Can you please explain what does this code do?