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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 percent_value(self, percent):
 """ Returns the time value at ``percent`` of this interval. :param percent: the percent :type percent: :class:`~aeneas.exacttiming.Decimal` :raises TypeError: if ``time_point`` is not an instance of ``TimeValue`` :rtype: :class:`~aeneas.exacttiming.TimeValue` """

        if not isinstance(percent, Decimal):
            raise TypeError(u"percent is not an instance of Decimal")
        percent = Decimal(max(min(percent, 100), 0) / 100)
        return self.begin + self.length * percent