def publish(self, cart, env=None):
        """
        `cart` - Release cart to publish in json format

        Publish a release cart in JSON format to the pre-release environment.
        """
        juicer.utils.Log.log_debug("Initializing publish of cart '%s'" % cart.cart_name)

        if not env:
            env = self._defaults['start_in']

        cart_id = juicer.utils.upload_cart(cart, env)
        juicer.utils.Log.log_debug('%s uploaded with an id of %s' %
                                   (cart.cart_name, cart_id))
        return True
`cart` - Release cart to publish in json format

        Publish a release cart in JSON format to the pre-release environment.