code: def sync_firmware(self):
          
          serial_no = self.serial_number
  
          if self.firmware_newer():
              # The J-Link's firmware is newer than the one compatible with the
              # DLL (though there are promises of backwards compatibility), so
              # perform a downgrade.
              try:
                  # This may throw an exception on older versions of the J-Link
                  # software due to the software timing out after a firmware
                  # upgrade.
                  self.invalidate_firmware()
                  self.update_firmware()
              except errors.JLinkException as e:
                  pass
  
              res = self.open(serial_no=serial_no)
  
              if self.firmware_newer():
                  raise errors.JLinkException('Failed to sync firmware version.')
  
              return res
  
          elif self.firmware_outdated():
              # The J-Link's firmware is older than the one compatible with the
              # DLL, so perform a firmware upgrade.
              try:
                  # This may throw an exception on older versions of the J-Link
                  # software due to the software timing out after a firmware
                  # upgrade.
                  self.update_firmware()
              except errors.JLinkException as e:
                  pass
  
              if self.firmware_outdated():
                  raise errors.JLinkException('Failed to sync firmware version.')
  
              return self.open(serial_no=serial_no)
  
          return None
docs: Syncs the emulator's firmware version and the DLL's firmware.
  
          This method is useful for ensuring that the firmware running on the
          J-Link matches the firmware supported by the DLL.
  
          Args:
            self (JLink): the ``JLink`` instance
  
          Returns:
            ``None``