code: def _add_delta(self, delta):
          
          new_values = super()._add_delta(delta)
          return type(self)._from_sequence(new_values, tz=self.tz, freq='infer')
docs: Add a timedelta-like, Tick, or TimedeltaIndex-like object
          to self, yielding a new DatetimeArray
  
          Parameters
          ----------
          other : {timedelta, np.timedelta64, Tick,
                   TimedeltaIndex, ndarray[timedelta64]}
  
          Returns
          -------
          result : DatetimeArray