code: def unique(values):
      values = _ensure_arraylike(values)
      if is_extension_array_dtype(values):
          return values.unique()
      original = values
      htable, _, values, dtype, ndtype = _get_hashtable_algo(values)
      table = htable(len(values))
      uniques = table.unique(values)
      uniques = _reconstruct_data(uniques, dtype, original)
      return uniques