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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 get_price_as_of(self, stock: Commodity, on_date: datetime):
 """ Gets the latest price on or before the given date. """

        # return self.get_price_as_of_query(stock, on_date).first()
        prices = PriceDbApplication()
        prices.get_prices_on(on_date.date().isoformat(), stock.namespace, stock.mnemonic)