text: class EmptyBasketException(Exception):
      pass
  
  
  class MissingShippingAddressException(Exception):
      pass
  
  
  class MissingShippingMethodException(Exception):
      pass
  
  
  class InvalidBasket(Exception):
      """
      For when the user's basket can't be submitted (eg it has zero cost)
  
      The message of this exception is shown to the customer.
      """
  