code: def _read_instrument(self) -> Dict[InstKT, InstVT]:
      if not self.uri.exists():
          self._write_instrument()
  
      _instruments = dict()
      df = pd.read_csv(
          self.uri,
          sep="\t",
          usecols=[0, 1, 2],
          names=[
              self.SYMBOL_FIELD_NAME,
              self.INSTRUMENT_START_FIELD,
              self.INSTRUMENT_END_FIELD,
          ],
          dtype={self.SYMBOL_FIELD_NAME: str},
          parse_dates=[
              self.INSTRUMENT_START_FIELD,
              self.INSTRUMENT_END_FIELD,
          ],
      )
      for row in df.itertuples(index=False):
          _instruments.setdefault(row[0], []).append((row[1], row[2]))
      return _instruments
  
imports: import struct
  from pathlib import Path
  from typing import Iterable, Union, Dict, Mapping, Tuple, List
  import numpy
  import pandas
  from qlib.utils.time import Freq
  from qlib.utils.resam import resam_calendar
  from qlib.config import C
  from qlib.data.cache import H
  from qlib.log import get_module_logger
  from qlib.data.storage import CalendarStorage, InstrumentStorage, FeatureStorage, CalVT, InstKT, InstVT
label_desc: Use image node_id 2 for calling the FileInstrumentStorage obj's underlying member method code with example usage: obj._read_instrument() and returns: _instruments