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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 wsgiref_thread_arbiter(wsgi, host, port):
    'probably not suitable for production use; example of threaded server'
    import wsgiref.simple_server
    httpd = wsgiref.simple_server.make_server(host, port, wsgi)
    httpd.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

    def start_server():
        server_thread = threading.Thread(target=httpd.serve_forever)
        server_thread.daemon = True
        server_thread.start()

    def close_socket():
        httpd.socket.close()

    arbiter = Arbiter(post_fork=start_server, child_pre_exit=httpd.shutdown,
                      parent_pre_stop=close_socket)
    return arbiter