code: def publish(self, cart, env=None):
          
          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
docs: `cart` - Release cart to publish in json format
  
          Publish a release cart in JSON format to the pre-release environment.