code: def get_cart(base_url, env, cart_name):
      
      base_url = base_url.replace('/pulp/api/', '/pulp/repos')
      url = '%s/%s/carts/%s.json' % (base_url, env, cart_name)
  
      rsock = urllib2.urlopen(url)
      data = rsock.read()
      rsock.close()
  
      return load_json_str(data)
docs: returns a dict object representing a cart stored in pulp
  
      base_url: a str for the base_url (eg: http://sweet.pulp.repo/pulp/api/)
      env: a str with the the name of the environement (eg: prod)
      cart_name: a str with the name of the cart to get