code: def debug_tag(self, tag):
          
          self.log.info('Logging debug tag set to "%s"', tag)
          self._debug_tag = tag
          self.log.extra['tag'] = tag
docs: Setter for the debug tag.
  
          By default, the tag is the serial of the device, but sometimes it may
          be more descriptive to use a different tag of the user's choice.
  
          Changing debug tag changes part of the prefix of debug info emitted by
          this object, like log lines and the message of DeviceError.
  
          Example:
              By default, the device's serial number is used:
                  'INFO [AndroidDevice|abcdefg12345] One pending call ringing.'
              The tag can be customized with `ad.debug_tag = 'Caller'`:
                  'INFO [AndroidDevice|Caller] One pending call ringing.'