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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def index(req, res):
 """ Return root page of website. """

    number = req.session.get('counter', -1)
    req.session['counter'] = int(number) + 1
    print(" -- Session '{id}' returned {counter} times".format(**req.session))
    msg = "Hello!! You've been here [[%s]] times" % (req.session['counter'])
    res.send_text(msg)
    req.session.save()