def remove(self): raise Unavailable('remove the product from the card.')
def quantity(self): raise Unavailable('determine the product quantity.')
def add(self): raise Unavailable('add the product to the card.')
def price(self): raise Unavailable('determine the product price.')
def vendor_code(self): raise Unavailable('determine the vendor code.')
def price(self): raise Unavailable('determine the position price.')
def name(self): raise Unavailable('determine the position name.')
def name(self): raise Unavailable('determine the product name.')