class_docstr: The correctness of the metrics of Account in nested execution depends on the shallow copy of `trade_account` in
  qlib/backtest/executor.py:NestedExecutor
  Different level of executor has different Account object when calculating metrics. But the position object is
  shared cross all the Account object.
docstr: get the trade indicator instance, which has pa/pos/ffr info.
docstr_tok: ["get","the","trade","indicator","instance",",","which","has","pa\/pos\/ffr","info","."]
code: def get_trade_indicator(self) -> Indicator:
      """get the trade indicator instance, which has pa/pos/ffr info."""
      return self.indicator
  
imports: from __future__ import annotations
  import copy
  from typing import Dict, List, Optional, Tuple, cast
  import pandas
  from qlib.utils import init_instance_by_config
  from .decision import BaseTradeDecision, Order
  from .exchange import Exchange
  from .high_performance_ds import BaseOrderIndicator
  from .position import BasePosition
  from .report import Indicator, PortfolioMetrics
label_desc: Use image node_id 16 for calling the Account obj's underlying member method code with example usage: obj.get_trade_indicator() and returns: self