Group By in Core Data

gistfile1.m

    NSFetchRequest *request = [self fetchRequestForType:CORE_DATA_BLOCK_TYPE];
    
    NSEntityDescription* entity = [NSEntityDescription entityForName:CORE_DATA_BLOCK_TYPE
                                              inManagedObjectContext:self.managedObjectContext];
    NSAttributeDescription* typeDesc = [entity.attributesByName objectForKey:@"type"];
    NSExpression *countExpression = [NSExpression expressionForFunction: @"count:"
                                                              arguments: [NSArray arrayWithObject:[NSExpression expressionForKeyPath: @"type"]]];
    NSExpressionDescription *expressionDescription = [[NSExpressionDescription alloc] init];
    [expressionDescription setName: @"count"];
    [expressionDescription setExpression: countExpression];
    [expressionDescription setExpressionResultType: NSInteger32AttributeType];
    
    [request setPropertiesToFetch:[NSArray arrayWithObjects:typeDesc, expressionDescription, nil]];
    [request setPropertiesToGroupBy:[NSArray arrayWithObject:typeDesc]];
    [request setResultType:NSDictionaryResultType];
    if (notebook)
        [request setPredicate:[NSPredicate predicateWithFormat:@"%@ in notebooks AND isSearchable == TRUE AND transient == FALSE", notebook.block]];
    else
        [request setPredicate:[NSPredicate predicateWithFormat:@"isSearchable == TRUE AND transient == FALSE"]];

    
    NSError* error = nil;
    NSArray *results = [self.managedObjectContext executeFetchRequest:request error:&error];

Hello ,is there a way to group by expressionDescription