code: def neighbours(self, healpix_index):
          
          return neighbours(healpix_index, self.nside, order=self.order)
docs: Find all the HEALPix pixels that are the neighbours of a HEALPix pixel
  
          Parameters
          ----------
          healpix_index : `~numpy.ndarray`
              Array of HEALPix pixels
  
          Returns
          -------
          neigh : `~numpy.ndarray`
              Array giving the neighbours starting SW and rotating clockwise. This has
              one extra dimension compared to ``healpix_index`` - the first dimension -
              which is set to 8. For example if healpix_index has shape (2, 3),
              ``neigh`` has shape (8, 2, 3).