'Helper method for converting deprecated limit_price and stop_price
arguments into ExecutionStyle instances.
This function assumes that either style == None or (limit_price,
stop_price) == (None, None).'

@staticmethod
def __convert_order_params_for_blotter(limit_price, stop_price, style):

    if style:
        assert ((limit_price, stop_price) == (None, None))
        return style
    if (limit_price and stop_price):
        return StopLimitOrder(limit_price, stop_price)
    if limit_price:
        return LimitOrder(limit_price)
    if stop_price:
        return StopOrder(stop_price)
    else:
        return MarketOrder()
