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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def marketPrice(self) -> float: """ Return the first available one of * last price if within current bid/ask; * average of bid and ask (midpoint); * close price. """

        price = self.last if (
            self.hasBidAsk() and self.bid <= self.last <= self.ask) else \
            self.midpoint()
        if isNan(price):
            price = self.close
        return price