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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 rpc_call(payload):
 """Simple Flask implementation for making asynchronous Rpc calls. """


    # Send the request and store the requests Unique ID.
    corr_id = RPC_CLIENT.send_request(payload)

    # Wait until we have received a response.
    while RPC_CLIENT.queue[corr_id] is None:
        sleep(0.1)

    # Return the response to the user.
    return RPC_CLIENT.queue[corr_id]