code: def create(self, cart_name, cart_description):
          
          cart = juicer.common.Cart.Cart(cart_name)
  
          # repo_items is a list that starts with the REPO name,
          # followed by the ITEMS going into the repo.
          for repo_items in cart_description:
              (repo, items) = (repo_items[0], repo_items[1:])
              juicer.utils.Log.log_debug("Processing %s input items for repo '%s'." % (len(items), repo))
              cart[repo] = items
  
          cart.save()
          return cart
docs: `cart_name` - Name of this release cart
          `cart_description` - list of ['reponame', item1, ..., itemN] lists