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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 default_callback(pending, timeout):
 """This is the default shutdown callback that is set on the options. It prints out a message to stderr that informs the user that some events are still pending and the process is waiting for them to flush out. """


    def echo(msg):
        sys.stderr.write(msg + "\n")

    echo("Sentry is attempting to send %i pending error messages" % pending)
    echo("Waiting up to %s seconds" % timeout)
    echo("Press Ctrl-%s to quit" % (os.name == "nt" and "Break" or "C"))
    sys.stderr.flush()