code: def __call__(
      self, trade_calendar: TradeCalendarManager | None = None
  ) -> Tuple[int, int]:
      return self._start_idx, self._end_idx
  
imports: from __future__ import annotations
  from abc import abstractmethod
  from datetime import time
  from enum import IntEnum
  from typing import TYPE_CHECKING, Any, ClassVar, Generic, List, Optional, Tuple, TypeVar, Union, cast
  from qlib.backtest.utils import TradeCalendarManager
  from qlib.data.data import Cal
  from qlib.log import get_module_logger
  from qlib.utils.time import concat_date_time, epsilon_change
  from dataclasses import dataclass
  import numpy
  import pandas
label_desc: Use image node_id 2 for calling the IdxTradeRange obj's underlying member method code with example usage: obj.__call__(trade_calendar) and returns: self,  self