code: def _postprocess(self, x, out=None):
          
          if out is None:
              if self.domain.field == ComplexNumbers():
                  out = self._tmp_r if self._tmp_r is not None else self._tmp_f
              else:
                  out = self._tmp_f
          return dft_postprocess_data(
              out, real_grid=self.domain.grid, recip_grid=self.range.grid,
              shift=self.shifts, axes=self.axes, sign=self.sign,
              interp=self.domain.interp, op='multiply', out=out)
docs: Return the post-processed version of ``x``.
  
          C2C: use ``tmp_f`` (C2C operation)
          R2C: use ``tmp_f`` (C2C operation)
          HALFC: use ``tmp_f`` (C2C operation)
  
          The result is stored in ``out`` if given, otherwise in
          a temporary or a new array.