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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_earliest_valid_timestamp(self, symbol, interval):
 """Get earliest valid open timestamp from Binance :param symbol: Name of symbol pair e.g BNBBTC :type symbol: str :param interval: Binance Kline interval :type interval: str :return: first valid timestamp """

        kline = self.get_klines(
            symbol=symbol,
            interval=interval,
            limit=1,
            startTime=0,
            endTime=None
        )
        return kline[0][0]