class_docstr: Provides methods for retrieving daily stock data from
  Yahoo Finance API
  
  Attributes
  ----------
      start_date : str
          start date of the data (modified from neofinrl_config.py)
      end_date : str
          end date of the data (modified from neofinrl_config.py)
      ticker_list : list
          a list of stock tickers (modified from neofinrl_config.py)
  
  Methods
  -------
  fetch_data()
      Fetches data from yahoo API
code: def __init__(self, start_date: str, end_date: str, ticker_list: list):
      self.start_date = start_date
      self.end_date = end_date
      self.ticker_list = ticker_list
  
imports: from __future__ import annotations
  import pandas
  import yfinance
label_desc: Use image node_id 1 to create a new YahooDownloader object  with example: obj = YahooDownloader(start_date, end_date, ticker_list)