modified

app.py

@@ -116,8 +116,9 @@ def add_tasks(roadmap, tasks):
             subject_entry = next((sub for sub in day["teacher_tasks"] if sub["name"] == subject_name), None)
 
             if subject_entry:
-                if new_tasks not in subject_entry["tasks"]:
-                    subject_entry["tasks"].extend(new_tasks)
+                for task in new_tasks:
+                    if task not in subject_entry["tasks"]:
+                        subject_entry["tasks"].append(task)
             else:
                 day["teacher_tasks"].append({
                     "name": subject_name,