docs: def extract_slitlet2d(self, image_2k2k):
          """Extract slitlet 2d image from image with original EMIR dimensions.
  
          Parameters
          ----------
          image_2k2k : numpy array
              Original image (dimensions EMIR_NAXIS1 * EMIR_NAXIS2)
  
          Returns
          -------
          slitlet2d : numpy array
              Image corresponding to the slitlet region defined by its
              bounding box.
  
          """
  
          # protections
          naxis2, naxis1 = image_2k2k.shape
          if naxis1 != EMIR_NAXIS1:
              raise ValueError('Unexpected naxis1')
          if naxis2 != EMIR_NAXIS2:
              raise ValueError('Unexpected naxis2')
  
          # extract slitlet region
          slitlet2d = image_2k2k[(self.bb_ns1_orig - 1):self.bb_ns2_orig,
                                 (self.bb_nc1_orig - 1):self.bb_nc2_orig]
  
          # transform to float
          slitlet2d = slitlet2d.astype(np.float)
  
          # display slitlet2d with boundaries and middle spectrum trail
          if abs(self.debugplot) in [21, 22]:
              self.ximshow_unrectified(slitlet2d)
  
          # return slitlet image
          return slitlet2d