Creates an XDR Operation object that represents this
        :class:`ManageOffer`.

def to_xdr_object(self):
        """Creates an XDR Operation object that represents this
        :class:`ManageOffer`.

        """
        selling = self.selling.to_xdr_object()
        buying = self.buying.to_xdr_object()
        price = Operation.to_xdr_price(self.price)
        price = Xdr.types.Price(price['n'], price['d'])

        amount = Operation.to_xdr_amount(self.amount)

        manage_offer_op = Xdr.types.ManageOfferOp(selling, buying, amount,
                                                  price, self.offer_id)
        self.body.type = Xdr.const.MANAGE_OFFER
        self.body.manageOfferOp = manage_offer_op
        return super(ManageOffer, self).to_xdr_object()