code: def _fetch_data_for_ticker(
      self, ticker, start_date, end_date, time_interval
  ):
      bars = self.api.get_bars(
          ticker,
          time_interval,
          start=start_date.isoformat(),
          end=end_date.isoformat(),
      ).df
      bars["symbol"] = ticker
      return bars
  
imports: from __future__ import annotations
  from concurrent.futures import ProcessPoolExecutor
  from concurrent.futures import ThreadPoolExecutor
  import alpaca_trade_api
  import exchange_calendars
  import numpy
  import pandas
  import pytz
  from stockstats import StockDataFrame
label_desc: Use image node_id 2 for calling the AlpacaProcessor obj's underlying member method code with example usage: obj._fetch_data_for_ticker(ticker, start_date, end_date, time_interval) and returns: bars