Create billing.py

billing.py

@@ -0,0 +1,8 @@
+def fetch_billing(patient_id, data):
+    if patient_id not in data:
+        return "Invalid Patient ID. Please check the ID."
+
+    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}"