code: def generate_span_requests(self, span_datas):
          
  
          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)
docs: 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.