code: def sortlevel(self, level=None, ascending=True, sort_remaining=None):
          
          return self.sort_values(return_indexer=True, ascending=ascending)
docs: For internal compatibility with with the Index API.
  
          Sort the Index. This is for compat with MultiIndex
  
          Parameters
          ----------
          ascending : boolean, default True
              False to sort in descending order
  
          level, sort_remaining are compat parameters
  
          Returns
          -------
          Index