text: Title: Stooq: futures, indices, cash, currency, bond yield tickers don't feed
  Body: Hello,
  
  I'm trying to scrape multiple historical quotes from Stooq. Equities and indicies work well, while futures, indices, cash, currency, bond yield don't feed. Shall I type the tickers somehow differently?
  
  Below is the code example with the tickers that don't work for me. 
  
  ```py
  now = datetime.now().date()
  stooq_tickers = ['PLN_I', 'DX.F', 'FX.C', 'U4.F', 'USDAUD', '10CNY.B', 'UKOUSD6M']
  
  stooqdf = dr.get_data_stooq(stooq_tickers, start='2016-01-01', end=now)
  ```
  
  Also is there a way to feed economic data, for example 'PMMNCN.M' or 'IMPRCN.M'?
  Thank you in advance for any help!