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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 generate_span_requests(self, span_datas):
 """Span request generator. :type span_datas: list of :class:`~opencensus.trace.span_data.SpanData` :param span_datas: SpanData tuples to convert to protobuf spans and send to opensensusd agent :rtype: list of `~gen.opencensus.agent.trace.v1.trace_service_pb2.ExportTraceServiceRequest` :returns: List of span export requests. """


        pb_spans = [
            utils.translate_to_trace_proto(span_data)
            for span_data in span_datas
        ]

        # TODO: send node once per channel
        yield trace_service_pb2.ExportTraceServiceRequest(
            node=self.node,
            spans=pb_spans)