code: def percent_value(self, percent):
          
          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
docs: 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`