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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 _guessunit(self):
 """Guess the unit of the period as the largest one, which results in an integer duration. """

        if not self.days % 1:
            return 'd'
        elif not self.hours % 1:
            return 'h'
        elif not self.minutes % 1:
            return 'm'
        elif not self.seconds % 1:
            return 's'
        else:
            raise ValueError(
                'The stepsize is not a multiple of one '
                'second, which is not allowed.')