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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 launch_shell(username, hostname, password, port=22):
 """ Launches an ssh shell """

    if not username or not hostname or not password:
        return False

    with tempfile.NamedTemporaryFile() as tmpFile:
        os.system(sshCmdLine.format(password, tmpFile.name, username, hostname,
                                    port))
    return True