'Extract only the operating system type from the active histogram.'

def GetReportData(self, get_report_args, token):

    ret = rdf_report_plugins.ApiReportData(representation_type=rdf_report_plugins.ApiReportData.RepresentationType.PIE_CHART)
    try:
        fd = aff4.FACTORY.Open(rdfvalue.RDFURN('aff4:/stats/ClientFleetStats').Add(get_report_args.client_label), token=token)
        for graph in fd.Get(aff4_stats.ClientFleetStats.SchemaCls.RELEASE_HISTOGRAM):
            if (('%s    day' % self.__class__.ACTIVE_DAYS) in graph.title):
                for sample in graph:
                    ret.pie_chart.data.Append(rdf_report_plugins.ApiReportDataPoint1D(label=sample.label, x=sample.y_value))
                break
    except (IOError, TypeError):
        pass
    ret.pie_chart.data = sorted(ret.pie_chart.data, key=(lambda point: point.label))
    return ret
