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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 prepend_zeros(self, num):
 """Prepend num zeros onto the beginning of this TimeSeries. Update also epoch to include this prepending. """

        self.resize(len(self) + num)
        self.roll(num)
        self._epoch = self._epoch - num * self._delta_t