NSOpenPanel* panel = [NSOpenPanel openPanel];
    [panel setMessage:@"Select Folder"];
    [panel setPrompt:@"Select"];
    [panel setCanChooseFiles:NO];
    [panel setCanChooseDirectories:YES];
    [panel beginSheetModalForWindow:self.window completionHandler:^(NSModalResponse returnCode) {
        NSString* path = [[panel URL] path];
    }];