code: def normalize_date_format(date_str, default_time="00:00:00"):
      
      ret_code, ret_data = check_date_str_format(date_str, default_time)
      if ret_code != RET_OK:
          return ret_code, ret_data
  
      return RET_OK, ret_data.strftime("%Y-%m-%d %H:%M:%S")
docs: normalize the format of data