code: def log_download(self, log_num, filename):
          '''download a log file'''
          print("Downloading log %u as %s" % (log_num, filename))
          self.download_lognum = log_num
          self.download_file = open(filename, "wb")
          self.master.mav.log_request_data_send(self.target_system,
                                                     self.target_component,
                                                     log_num, 0, 0xFFFFFFFF)
          self.download_filename = filename
          self.download_set = set()
          self.download_start = time.time()
          self.download_last_timestamp = time.time()
          self.download_ofs = 0
          self.retries = f log_download(self, log_num, filename):
          '''download a log file'''
          print("Downloading log %u as %s" % (log_num, filename))
          self.download_lognum = log_num
          self.download_file = open(filename, "wb")
          self.master.mav.log_request_data_send(self.target_system,
                                                     self.target_component,
                                                     log_num, 0, 0xFFFFFFFF)
          self.download_filename = filename
          self.download_set = set()
          self.download_start = time.time()
          self.download_last_timestamp = time.time()
          self.download_ofs = 0
          self.retries = 0
docs: download a log file