code: def _GetAFF4AttributeForReportType(report_type
                                    ):
    
    if report_type == rdf_stats.ClientGraphSeries.ReportType.GRR_VERSION:
      return aff4_stats.ClientFleetStats.SchemaCls.GRRVERSION_HISTOGRAM
    elif report_type == rdf_stats.ClientGraphSeries.ReportType.OS_TYPE:
      return aff4_stats.ClientFleetStats.SchemaCls.OS_HISTOGRAM
    elif report_type == rdf_stats.ClientGraphSeries.ReportType.OS_RELEASE:
      return aff4_stats.ClientFleetStats.SchemaCls.RELEASE_HISTOGRAM
    elif report_type == rdf_stats.ClientGraphSeries.ReportType.N_DAY_ACTIVE:
      return aff4_stats.ClientFleetStats.SchemaCls.LAST_CONTACTED_HISTOGRAM
    else:
      raise ValueError("Unknown report type %s." % report_type)
docs: Returns the corresponding AFF4 attribute for the given report type.