code: def pad_to_aspect_ratio(self, aspect_ratio, mode="constant", cval=0.0, return_pad_amounts=False):
          
          arr_padded, pad_amounts = ia.pad_to_aspect_ratio(self.arr, aspect_ratio=aspect_ratio, mode=mode, cval=cval,
                                                           return_pad_amounts=True)
          segmap = SegmentationMapOnImage(arr_padded, shape=self.shape)
          segmap.input_was = self.input_was
          if return_pad_amounts:
              return segmap, pad_amounts
          else:
              return segmap
docs: Pad the segmentation map on its sides so that its matches a target aspect ratio.
  
          Depending on which dimension is smaller (height or width), only the corresponding
          sides (left/right or top/bottom) will be padded. In each case, both of the sides will
          be padded equally.
  
          Parameters
          ----------
          aspect_ratio : float
              Target aspect ratio, given as width/height. E.g. 2.0 denotes the image having twice
              as much width as height.
  
          mode : str, optional
              Padding mode to use. See :func:`numpy.pad` for details.
  
          cval : number, optional
              Value to use for padding if `mode` is ``constant``. See :func:`numpy.pad` for details.
  
          return_pad_amounts : bool, optional
              If False, then only the padded image will be returned. If True, a tuple with two
              entries will be returned, where the first entry is the padded image and the second
              entry are the amounts by which each image side was padded. These amounts are again a
              tuple of the form (top, right, bottom, left), with each value being an integer.
  
          Returns
          -------
          segmap : imgaug.SegmentationMapOnImage
              Padded segmentation map as SegmentationMapOnImage object.
  
          pad_amounts : tuple of int
              Amounts by which the segmentation map was padded on each side, given as a
              tuple ``(top, right, bottom, left)``.
              This tuple is only returned if `return_pad_amounts` was set to True.