code: def screenshot(context):
      
      handler = lambda _, buff, file_handler: file_handler.write(buff)
  
      string = BytesIO()
      stream = context.domain.connect().newStream(0)
      context.domain.screenshot(stream, 0, 0)
      stream.recvAll(handler, string)
  
      return string.getvalue()
docs: Takes a screenshot of the vnc connection of the guest.
      The resulting image file will be in Portable Pixmap format (PPM).
  
      @param context: (see.Context) context of the Environment.
      @return: (str) binary stream containing the screenshot.