internal static ILookup <string, Microsoft.Exchange.MessagingPolicies.Rules.Rule> GetDataClassificationsInUse(IConfigDataProvider tenantSession, IEnumerable <string> dataClassificationIds, IEqualityComparer <string> dataClassificationIdComparer = null) { ArgumentValidator.ThrowIfNull("tenantSession", tenantSession); ArgumentValidator.ThrowIfNull("dataClassificationIds", dataClassificationIds); if (!dataClassificationIds.Any <string>()) { return(Enumerable.Empty <Microsoft.Exchange.MessagingPolicies.Rules.Rule>().ToLookup((Microsoft.Exchange.MessagingPolicies.Rules.Rule rule) => null)); } ADRuleStorageManager adruleStorageManager = new ADRuleStorageManager(Utils.RuleCollectionNameFromRole(), tenantSession); adruleStorageManager.LoadRuleCollection(); return(DlpUtils.GetDataClassificationsReferencedByRuleCollection(adruleStorageManager.GetRuleCollection(), dataClassificationIds, dataClassificationIdComparer)); }