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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 get_node(service_name, host_name):
 """Generates Node message from params and system information. """

    return common_pb2.Node(
        identifier=common_pb2.ProcessIdentifier(
            host_name=socket.gethostname() if host_name is None
            else host_name,
            pid=os.getpid(),
            start_timestamp=proto_ts_from_datetime(
                datetime.datetime.utcnow())),
        library_info=common_pb2.LibraryInfo(
            language=common_pb2.LibraryInfo.Language.Value('PYTHON'),
            exporter_version=EXPORTER_VERSION,
            core_library_version=opencensus_version),
        service_info=common_pb2.ServiceInfo(name=service_name))