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
def prepend_zeros ( self , num ) : self . resize ( len ( self ) + num ) self . roll ( num ) self . _epoch = self . _epoch - num * self . _delta_t
Prepend num zeros onto the beginning of this TimeSeries. Update also
        epoch to include this prepending.