docs: def guest_capture(self, userid, image_name, capture_type='rootonly',
                        compress_level=6):
          """ Capture the guest to generate a image
  
          :param userid: (str) the user id of the vm
          :param image_name: (str) the unique image name after capture
          :param capture_type: (str) the type of capture, the value can be:
                 rootonly: indicate just root device will be captured
                 alldisks: indicate all the devices of the userid will be
                 captured
          :param compress_level: the compression level of the image, default
                 is 6
          """
          action = ("capture guest '%(vm)s' to generate image '%(img)s'" %
                    {'vm': userid, 'img': image_name})
          with zvmutils.log_and_reraise_sdkbase_error(action):
              self._vmops.guest_capture(userid, image_name,
                                        capture_type=capture_type,
                                        compress_level=compress_level)