code: def _integ(img, r, c, rl, cl):
      """Integrate over the integral image in the given window
  
      This method was created so that `hessian_det_appx` does not have to make
      a Python call.
  
      Parameters
      ----------
      img : array
          The integral image over which to integrate.
      r : int
          The row number of the top left corner.
      c : int
          The column number of the top left corner.
      rl : int
          The number of rows over which to integrate.
      cl : int
          The number of columns over which to integrate.
  
      Returns
      -------
      ans : int
          The integral over the given window.
      """
  
      r = _clip(r, 0, img.shape[0] - 1)
      c = _clip(c, 0, img.shape[1] - 1)
  
      r2 = _clip(r + rl, 0, img.shape[0] - 1)
      c2 = _clip(c + cl, 0, img.shape[1] - 1)
  
      ans = img[r, c] + img[r2, c2] - img[r, c2] - img[r2, c]
      return max(0, ans)
  
imports: import numpy
label_desc: Use image node_id 2 for calling a global function with example usage: _integ(img, r, c, rl, cl) and returns: max