Update billing.py

billing.py

@@ -5,4 +5,4 @@ def fetch_billing(patient_id, data):
     patient_data = data[patient_id]
     test_list = ', '.join(patient_data["tests"])
     total_cost = patient_data["total_cost"]
-    return f"Patient: {patient_data['name']}\nTests: {test_list}\nTotal Bill: {total_cost}"
+    return f"Patient: {patient_data['name']}\nTests: {test_list}\nTotal Bill: ₹{total_cost}"