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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 periodic_service_rpcs(self):
 """Check if any RPC has expired and remove it from the in flight list. This function should be called periodically to expire any RPCs that never complete. """


        to_remove = []

        now = monotonic()
        for rpc_tag, rpc in self.in_flight_rpcs.items():
            expiry = rpc.sent_timestamp + rpc.timeout
            if now > expiry:
                to_remove.append(rpc_tag)

        for tag in to_remove:
            del self.in_flight_rpcs[tag]