code: def reindex(self, target, method=None, level=None, limit=None,
                  tolerance=None):
          
          # GH6552: preserve names when reindexing to non-named target
          # (i.e. neither Index nor Series).
          preserve_names = not hasattr(target, 'names')
  
          if level is not None:
              if method is not None:
                  raise TypeError('Fill method not supported if level passed')
  
              # GH7774: preserve dtype/tz if target is empty and not an Index.
              # target may be an iterator
              target = ibase._ensure_has_len(target)
              if len(target) == 0 and not isinstance(target, Index):
                  idx = self.levels[level]
                  attrs = idx._get_attributes_dict()
                  attrs.pop('freq', None)  # don't preserve freq
                  target = type(idx)._simple_new(np.empty(0, dtype=idx.dtype),
                                                 **attrs)
              else:
                  target = ensure_index(target)
              target, indexer, _ = self._join_level(target, level, how='right',
                                                    return_indexers=True,
                                                    keep_order=False)
          else:
              target = ensure_index(target)
              if self.equals(target):
                  indexer = None
              else:
                  if self.is_unique:
                      indexer = self.get_indexer(target, method=method,
                                                 limit=limit,
                                                 tolerance=tolerance)
                  else:
                      raise ValueError("cannot handle a non-unique multi-index!")
  
          if not isinstance(target, MultiIndex):
              if indexer is None:
                  target = self
              elif (indexer >= 0).all():
                  target = self.take(indexer)
              else:
                  # hopefully?
                  target = MultiIndex.from_tuples(target)
  
          if (preserve_names and target.nlevels == self.nlevels and
                  target.names != self.names):
              target = target.copy(deep=False)
              target.names = self.names
  
          return target, indexer
docs: Create index with target's values (move/add/delete values as necessary)
  
          Returns
          -------
          new_index : pd.MultiIndex
              Resulting index
          indexer : np.ndarray or None
              Indices of output values in original index.