For Groups, do I use the Container to set the application on a Permission Check Options object?

I am in the middle of converting the obsolete INodePermissions to use the IPermissions.

Below is my code that I have a question on. The "PermissionCheckOptions" object has contents and applications, but not the container.. that doesn't seem right to me as far as the permission checks are concerned.

maybe it is... I think it works.

using Telligent.Evolution.Extensibility.Urls.Version1;
using Telligent.Evolution.Extensibility.Api.Entities.Version1;
using TEApis = Telligent.Evolution.Extensibility.Apis;
using TEApiV1 = Telligent.Evolution.Extensibility.Api.Version1;
using TEApiV2 = Telligent.Evolution.Extensibility.Api.Version2;         
         ...
            // Group Container Type
            Guid containerTypeId = TEApis.Get<TEApiV1.IGroups>().ContainerTypeId;
            // Type the groupItem and cast as ContextItem
            ContextItem groupItem = (ContextItem) pageContext.ContextItems.Find(i => i.ContentTypeId == containerTypeId);
            // cast groupItem Guid?  to a Guid
            Guid containerId = (Guid)groupItem.ContainerId;
            // Get the accessing user
            int accessing_userId = TEApis.Get<TEApiV1.IUsers>().AccessingUser.Id.Value;
            // Get the ModifyGroup Permission Guid
            Guid Group_ModifyGroup_PermissionId = TEApis.Get<TEApiV1.IGroupPermissions>().ModifyGroup;
            // Initializ the Permission Check Option object
            TEApiV2.PermissionCheckOptions permissionCheckOptions = new TEApiV2.PermissionCheckOptions();
            // This is not intutive, as there is only Content and Applications.
            // So, we must use the Application, based on the group container.
            permissionCheckOptions.ApplicationId = containerId;
            permissionCheckOptions.ApplicationTypeId = containerTypeId;
            // finally, check the permissions
            PermissionCheck modifyGroup = TEApis.Get<TEApiV2.IPermissions>().CheckPermission(Group_ModifyGroup_PermissionId, accessing_userId, permissionCheckOptions);