code: def boottime():
      
      global __boottime
  
      if __boottime is None:
          up = uptime()
          if up is None:
              return None
      if __boottime is None:
          _boottime_linux()
  
      if datetime is None:
          raise RuntimeError('datetime module required.')
  
      return datetime.fromtimestamp(__boottime or time.time() - up)
docs: Returns boot time if remotely possible, or None if not.