code: def reorder_levels(self, order):
          
          order = [self._get_level_number(i) for i in order]
          if len(order) != self.nlevels:
              raise AssertionError('Length of order must be same as '
                                   'number of levels (%d), got %d' %
                                   (self.nlevels, len(order)))
          new_levels = [self.levels[i] for i in order]
          new_codes = [self.codes[i] for i in order]
          new_names = [self.names[i] for i in order]
  
          return MultiIndex(levels=new_levels, codes=new_codes,
                            names=new_names, verify_integrity=False)
docs: Rearrange levels using input order. May not drop or duplicate levels
  
          Parameters
          ----------