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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 start_basic_span(self, request):
 """ Start tracing span from the protocol's `tracing` fields. This will only work if the `tracer` supports Zipkin-style span context. :param request: inbound request :type request: tchannel.tornado.request.Request """

        # noinspection PyBroadException
        try:
            # Currently Java does not populate Tracing field, so do not
            # mistaken it for a real trace ID.
            if request.tracing.trace_id:
                context = self.tracer.extract(
                    format=ZIPKIN_SPAN_FORMAT,
                    carrier=request.tracing)
                self.span = self.tracer.start_span(
                    operation_name=request.endpoint,
                    child_of=context,
                    tags={tags.SPAN_KIND: tags.SPAN_KIND_RPC_SERVER},
                )
        except opentracing.UnsupportedFormatException:
            pass  # tracer might not support Zipkin format
        except:
            log.exception('Cannot extract tracing span from Trace field')