code: def _get_interp_method(interp, sizes=()):
      
      if interp == 9:
          if sizes:
              assert len(sizes) == 4
              oh, ow, nh, nw = sizes
              if nh > oh and nw > ow:
                  return 2
              elif nh < oh and nw < ow:
                  return 3
              else:
                  return 1
          else:
              return 2
      if interp == 10:
          return random.randint(0, 4)
      if interp not in (0, 1, 2, 3, 4):
          raise ValueError('Unknown interp method %d' % interp)
      return interp
docs: Get the interpolation method for resize functions.
      The major purpose of this function is to wrap a random interp method selection
      and a auto-estimation method.
  
      Parameters
      ----------
      interp : int
          interpolation method for all resizing operations
  
          Possible values:
          0: Nearest Neighbors Interpolation.
          1: Bilinear interpolation.
          2: Area-based (resampling using pixel area relation). It may be a
          preferred method for image decimation, as it gives moire-free
          results. But when the image is zoomed, it is similar to the Nearest
          Neighbors method. (used by default).
          3: Bicubic interpolation over 4x4 pixel neighborhood.
          4: Lanczos interpolation over 8x8 pixel neighborhood.
          9: Cubic for enlarge, area for shrink, bilinear for others
          10: Random select from interpolation method metioned above.
          Note:
          When shrinking an image, it will generally look best with AREA-based
          interpolation, whereas, when enlarging an image, it will generally look best
          with Bicubic (slow) or Bilinear (faster but still looks OK).
          More details can be found in the documentation of OpenCV, please refer to
          http://docs.opencv.org/master/da/d54/group__imgproc__transform.html.
      sizes : tuple of int
          (old_height, old_width, new_height, new_width), if None provided, auto(9)
          will return Area(2) anyway.
  
      Returns
      -------
      int
          interp method from 0 to 4