code: def streaming_market_data_filter(fields=None, ladder_levels=None):
      
      args = locals()
      return {
          to_camel_case(k): v for k, v in args.items() if v is not None
      }
docs: :param list fields: EX_BEST_OFFERS_DISP, EX_BEST_OFFERS, EX_ALL_OFFERS, EX_TRADED,
      EX_TRADED_VOL, EX_LTP, EX_MARKET_DEF, SP_TRADED, SP_PROJECTED
      :param int ladder_levels: 1->10
  
      :return: dict