code: def __post_init__(self):
      assert maybe.map_or(self.index, len, len(self)) == len(self), (
          "Index has incorrect length. "
          f"Expected: {len(self)}, got {len(self.index)}."
      )
  
imports: from __future__ import annotations
  import dataclasses
  from operator import itemgetter
  from typing import Collection, Union, Optional, Dict, List, Tuple
  import numpy
  from toolz import first
  from gluonts import maybe
  from gluonts.itertools import pluck_attr
  from ._base import Pad, TimeBase
  from ._period import period, Period, Periods
  from ._util import AxisView, pad_axis, _replace
label_desc: Use image node_id 1 for calling the TimeSeries obj's underlying member method code with example usage: obj.__post_init__() without return types