docs: def _apply_loffset(grouper, result):
      """
      (copied from pandas)
      if loffset is set, offset the result index
  
      This is NOT an idempotent routine, it will be applied
      exactly once to the result.
  
      Parameters
      ----------
      result : Series or DataFrame
          the result of resample
      """
  
      needs_offset = (
          isinstance(grouper.loffset, (pd.DateOffset, datetime.timedelta))
          and isinstance(result.index, pd.DatetimeIndex)
          and len(result.index) > 0
      )
  
      if needs_offset:
          result.index = result.index + grouper.loffset
  
      grouper.loffset = None