How would I return a unique list 'listColl' I tried using 'Distinct9' at the bottom with 'return listColl;' but received an error.but it didnt work. Currently this return a duplicate list of items...

public List<SPWeb> GetAllWebs(string webURL)
{
    string url = System.Web.HttpUtility.UrlDecode(webURL);

    List<SPWeb> webColl = new List<SPWeb>();
    try
    {
        ClientContext clientContext = new ClientContext(url);
        Web oWebsite = clientContext.Web;

        clientContext.Load(oWebsite,
            website => website.Webs,
            website => website.Title,
            website => website.Id,
            website => website.ServerRelativeUrl
            );
        clientContext.ExecuteQuery();

        foreach (Web oneWeb in oWebsite.Webs)
        {
            webColl.Add(new SPWeb
            {
                Title = oneWeb.Title,
                WebGUID = oneWeb.Id.ToString(),
                ServerRelativeUrl = (url + oneWeb.ServerRelativeUrl).Replace(@"\", ""),
            });
        }
    }
    catch (Exception ex)
    {
        // error log
        string error = ex.Message + " Error within GetAllWebs ";
    }
    return webColl;
}

public List<SPList> GetAllLibraries(string webURL)
{
    var listColl = new List<SPList>();
    ClientContext _ctx = new ClientContext(webURL);
    try
    {
        var currentWeb = _ctx.Web;
        var AllLists = currentWeb.Lists;
        _ctx.Load(AllLists);
        _ctx.ExecuteQuery();
        var query = from list in currentWeb.Lists
                    where list.BaseType == BaseType.DocumentLibrary
                    select list;

        var listCollection = _ctx.LoadQuery(query.Include(myList => myList.Title,
                                      myList => myList.Id,
                                      myList => myList.RootFolder.ServerRelativeUrl,
                                      myList => myList.ParentWebUrl,
                                      myList => myList.Hidden,
                                      myList => myList.IsApplicationList));
        _ctx.ExecuteQuery();

      //   /*

        listColl.AddRange( (from list in listCollection
                           where !list.Hidden
                           select new SPList
                           {
                               Title = list.Title,
                               ListGUID = list.Id.ToString(),
                               RootFolderServerRelativeUrl = list.RootFolder.ServerRelativeUrl,
                               ParentWebUrl = list.ParentWebUrl
                           //below Distinct not working
                           }).Distinct() );

   // } */
        foreach (var Item in listCollection)
        {
            listColl.Add(new SPList
            {
                Title = Item.Title,
                RootFolderServerRelativeUrl = Item.RootFolder.ServerRelativeUrl,
                ListGUID = Item.Id.ToString()
            });
        }
    }
    catch (Exception ex)
    {
        // error log
        string error = ex.Message + " Error within GetAllLibraries ";
    }
    //return error
    //return listColl.Distinct();
    return listColl;
}