def remove(self, pk):
        """Remove an item from the cart.

        Parameters
        ----------
        pk : str or int
            The primary key of the item.

        Raises
        ------
        ItemNotInCart

        """
        pk = str(pk)
        try:
            del self.items[pk]
        except KeyError:
            raise ItemNotInCart(pk=pk)
        self.update()
Remove an item from the cart.

        Parameters
        ----------
        pk : str or int
            The primary key of the item.

        Raises
        ------
        ItemNotInCart