Read the code carefully

import logging, io

buf = io.StringIO()
h = logging.StreamHandler(buf)
h.setFormatter(logging.Formatter("%(levelname)s:%(message)s"))

log = logging.getLogger("demo")
log.handlers.clear()
log.addHandler(h)
log.setLevel(logging.INFO)

log.debug("hidden")
log.info("hello")
print(buf.getvalue().strip())

What will the program print? Write here: