code: def max_order(self):
          
          # TODO: cache value
          combo = int(0)
          for iv in self._interval_set._intervals:
              combo |= iv[0] | iv[1]
  
          ret = AbstractMOC.HPY_MAX_NORDER - (utils.number_trailing_zeros(combo) // 2)
          if ret < 0:
              ret = 0
  
          return ret
docs: Depth of the smallest HEALPix cells found in the MOC instance.