code: def is_(self, other):
          
          # use something other than None to be clearer
          return self._id is getattr(
              other, '_id', Ellipsis) and self._id is not None
docs: More flexible, faster check like ``is`` but that works through views.
  
          Note: this is *not* the same as ``Index.identical()``, which checks
          that metadata is also the same.
  
          Parameters
          ----------
          other : object
              other object to compare against.
  
          Returns
          -------
          True if both have same underlying data, False otherwise : bool