def marginBuy(self, currencyPair, rate, amount, lendingRate=None):
        """Places a margin buy order in a given market. Required POST
        parameters are "currencyPair", "rate", and "amount". You may optionally
         specify a maximum lending rate using the "lendingRate" parameter.
         If successful, the method will return the order number and any trades
         immediately resulting from your order."""
        return self._private('marginBuy', currencyPair=currencyPair, rate=rate,
                             amount=amount, lendingRate=lendingRate)
Places a margin buy order in a given market. Required POST
        parameters are "currencyPair", "rate", and "amount". You may optionally
         specify a maximum lending rate using the "lendingRate" parameter.
         If successful, the method will return the order number and any trades
         immediately resulting from your order.