code: def reboot(self, target_mode=None, timeout_ms=None):
      
      return self._simple_command('reboot', arg=target_mode,
                                  timeout_ms=timeout_ms)
docs: Reboots the device.
  
      Args:
          target_mode: Normal reboot when unspecified (or None). Can specify
              other target modes, such as 'recovery' or 'bootloader'.
          timeout_ms: Optional timeout in milliseconds to wait for a response.
      Returns:
          Usually the empty string. Depends on the bootloader and the target_mode.