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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 std(self):
 """ The standard deviation of the best results of each trial. Returns: float: standard deviation of measured seconds Note: As mentioned in the timeit source code, the standard deviation is not often useful. Typically the minimum value is most informative. Example: """

        import math
        chunk_iter = chunks(self.times, self.bestof)
        times = list(map(min, chunk_iter))
        mean = sum(times) / len(times)
        std = math.sqrt(sum((t - mean) ** 2 for t in times) / len(times))
        return std