code: def last(self, values, axis=0):
          
          values = np.asarray(values)
          return self.unique, np.take(values, self.index.sorter[self.index.stop-1], axis)
docs: return values at last occurance of its associated key
  
          Parameters
          ----------
          values : array_like, [keys, ...]
              values to pick the last value of per group
          axis : int, optional
              alternative reduction axis for values
  
          Returns
          -------
          unique: ndarray, [groups]
              unique keys
          reduced : ndarray, [groups, ...]
              value array, reduced over groups