function process_user(){
    #'''Call /delta for the given user ID and process any changes.'''
// creation d'un client dropbox
    include("lib/dropboxAPI.php");
    $myCustomClient = new dbx\Client($accessToken, $clientIdentifier);

    //Articles
    $pathPrefix="/Chargements appareil photo/ArticleTdm";
    $cursortxt = "lib/cursor.txt";
    $url="url";
    delta($myCustomClient ,$cursortxt, $url, $pathPrefix);

    //Challenge
    $pathPrefix="/Chargements appareil photo/ChallengeTdm";
    $cursortxt = "lib/cursorC.txt";
    $url="challenge_update";
    delta($myCustomClient , $cursortxt, $url, $pathPrefix);
}