old_contents: from QUANTAXIS.QAUtil import (QASETTING,QA_util_log_info)
  
  TIMEOUT = 10
  ILOVECHINA = "同学！！你知道什么叫做科学上网么？ 如果你不知道的话，那么就加油吧！"
  
  
  def QA_SU_save_symbols(fetch_symnol_func, exchange):
      symbols = fetch_symnol_func()
      col = QASETTING.client[exchange].symbols
      if col.find().count() == len(symbols):
          QA_util_log_info("{} SYMBOLS are already existed and no more to update".format(exchange))
      else:
          QA_util_log_info("Delete the original {} symbols collections".format(exchange))
          QASETTING.client.binance.drop_collection("symbols")
          QA_util_log_info("Downloading the new symbols")
          col.insert_many(symbols)
          QA_util_log_info("{} Symbols download is done! Thank you man!".format(exchange))
  
new_contents: from QUANTAXIS.QAUtil import (QASETTING,QA_util_log_info)
  
  TIMEOUT = 10
  ILOVECHINA = "同学！！你知道什么叫做科学上网么？ 如果你不知道的话，那么就加油吧！"
  
  
  def QA_SU_save_symbols(fetch_symnol_func, exchange):
      symbols = fetch_symnol_func()
      col = QASETTING.client[exchange].symbols
      if col.find().count() == len(symbols):
          QA_util_log_info("{} SYMBOLS are already existed and no more to update".format(exchange))
      else:
          QA_util_log_info("Delete the original {} symbols collections".format(exchange))
          QASETTING.client.exchange.drop_collection("symbols")
          QA_util_log_info("Downloading the new symbols")
          col.insert_many(symbols)
          QA_util_log_info("{} Symbols download is done! Thank you man!".format(exchange))
  
subject: correct exchange error