code: def _ensure_localized(self, arg, ambiguous='raise', nonexistent='raise',
                            from_utc=False):
          
  
          # reconvert to local tz
          tz = getattr(self, 'tz', None)
          if tz is not None:
              if not isinstance(arg, type(self)):
                  arg = self._simple_new(arg)
              if from_utc:
                  arg = arg.tz_localize('UTC').tz_convert(self.tz)
              else:
                  arg = arg.tz_localize(
                      self.tz, ambiguous=ambiguous, nonexistent=nonexistent
                  )
          return arg
docs: Ensure that we are re-localized.
  
          This is for compat as we can then call this on all datetimelike
          arrays generally (ignored for Period/Timedelta)
  
          Parameters
          ----------
          arg : Union[DatetimeLikeArray, DatetimeIndexOpsMixin, ndarray]
          ambiguous : str, bool, or bool-ndarray, default 'raise'
          nonexistent : str, default 'raise'
          from_utc : bool, default False
              If True, localize the i8 ndarray to UTC first before converting to
              the appropriate tz. If False, localize directly to the tz.
  
          Returns
          -------
          localized array