code: def add_technical_indicator(
      self, df, tech_indicator_list
  ) -> pd.DataFrame:
      self.tech_indicator_list = tech_indicator_list
      df = self.processor.add_technical_indicator(
          df, tech_indicator_list
      )
  
      return df
  
file_path: FinRL/finrl/meta/data_processor.py
imports: from __future__ import annotations
  import numpy
  import pandas
  from finrl.meta.data_processors.processor_alpaca import AlpacaProcessor
  from finrl.meta.data_processors.processor_wrds import WrdsProcessor
  from finrl.meta.data_processors.processor_yahoofinance import YahooFinanceProcessor
label_desc: Use image node_id 4 for calling the DataProcessor obj's underlying member method code with example usage: obj.add_technical_indicator(df, tech_indicator_list) and returns: df