static function countProjectTimeslots($allowedWorkspaceIdsCSV = null, $user = null, $project = null)
 {
     $project_sql = "";
     if ($allowedWorkspaceIdsCSV != null) {
         $project_sql .= " AND `object_id` IN ({$allowedWorkspaceIdsCSV})";
     }
     if ($project instanceof Project) {
         $pids = $project->getAllSubWorkspacesQuery();
         $project_sql .= " AND `object_id` IN ({$pids})";
     }
     $user_sql = "";
     if ($user instanceof User) {
         $user_sql = " AND user_id = " . $user->getId();
     }
     return Timeslots::count("object_manager = 'Projects'" . $project_sql . $user_sql);
 }