code: def retrieve(customer, card_id):
          
          if isinstance(customer, resources.Customer):
              customer = customer.id
  
          http_client = HttpClient()
          response, __ = http_client.get(routes.url(routes.CARD_RESOURCE, resource_id=card_id, customer_id=customer))
          return resources.Card(**response)
docs: Retrieve a card from its id.
  
          :param customer: The customer id or object
          :type customer: string|Customer
          :param card_id: The card id
          :type card_id: string
  
          :return: The customer resource
          :rtype: resources.Card