code: def to_perioddelta(self, freq):
          
          # TODO: consider privatizing (discussion in GH#23113)
          from pandas.core.arrays.timedeltas import TimedeltaArray
          i8delta = self.asi8 - self.to_period(freq).to_timestamp().asi8
          m8delta = i8delta.view('m8[ns]')
          return TimedeltaArray(m8delta)
docs: Calculate TimedeltaArray of difference between index
          values and index converted to PeriodArray at specified
          freq. Used for vectorized offsets
  
          Parameters
          ----------
          freq : Period frequency
  
          Returns
          -------
          TimedeltaArray/Index