Update app.py

app.py

@@ -31,8 +31,13 @@ Eine kreative {channel}-Kampagne für {product}, z. B. mit exklusiven Angebote
 """
 
 def add_campaign(name, goal, product, channel, start, end, budget, responsible):
-    if not isinstance(start, datetime) or not isinstance(end, datetime):
-        return pd.DataFrame(campaigns), "❌ Ungültiges Datum."
+    try:
+        if isinstance(start, str):
+            start = datetime.datetime.strptime(start, "%Y-%m-%d")
+        if isinstance(end, str):
+            end = datetime.datetime.strptime(end, "%Y-%m-%d")   
+    except Exception as e:
+        return pd.DataFrame(campaigns), f"❌ Ungültiges Datum: {e}"
     campaigns.append({
         "Name": name,
         "Ziel": goal,