Used for FX, etc:
        createCashContract("EUR", currency="USD")

def createCashContract(self, symbol, currency="USD", exchange="IDEALPRO"):
        """ Used for FX, etc:
        createCashContract("EUR", currency="USD")
        """
        contract_tuple = (symbol, "CASH", exchange, currency, "", 0.0, "")
        contract = self.createContract(contract_tuple)
        return contract