public List<string> InitialFolders()
    {
        List<string> foldersList = new List<string>();
        foreach (string siteUrl in bigList)
        {
            ClientContext clientcontext = new ClientContext(siteUrl);
            using (clientcontext)
            {
                _currFolder = clientcontext.Web.GetFolderByServerRelativeUrl(siteUrl+ "/MyList");
                clientcontext.Load(_currFolder);
                clientcontext.Load(_currFolder.Folders);
                clientcontext.ExecuteQuery();
                foreach (Folder sub_f in _currFolder.Folders)
                {
                        foldersList.Add(sub_f.Name);
                }
            }
        }
                return foldersList;
    }