Add batch polling to python code in batches docs (#11286)

docs/my-website/docs/batches.md

@@ -116,10 +116,38 @@ print("response from litellm.create_batch=", create_batch_response)
 **Retrieve the Specific Batch and File Content**
 
 ```python
+    # Maximum wait time before we give up
+    MAX_WAIT_TIME = 300  
+
+    # Time to wait between each status check
+    POLL_INTERVAL = 5
+    
+    #Time waited till now 
+    waited = 0
+
+    # Wait for the batch to finish processing before trying to retrieve output
+    # This loop checks the batch status every few seconds (polling)
+
+    while True:
+        retrieved_batch = await litellm.aretrieve_batch(
+            batch_id=create_batch_response.id,
+            custom_llm_provider="openai"
+        )
+        
+        status = retrieved_batch.status
+        print(f"⏳ Batch status: {status}")
+        
+        if status == "completed" and retrieved_batch.output_file_id:
+            print("✅ Batch complete. Output file ID:", retrieved_batch.output_file_id)
+            break
+        elif status in ["failed", "cancelled", "expired"]:
+            raise RuntimeError(f"❌ Batch failed with status: {status}")
+        
+        await asyncio.sleep(POLL_INTERVAL)
+        waited += POLL_INTERVAL
+        if waited > MAX_WAIT_TIME:
+            raise TimeoutError("❌ Timed out waiting for batch to complete.")
 
-retrieved_batch = await litellm.aretrieve_batch(
-    batch_id=create_batch_response.id, custom_llm_provider="openai"
-)
 print("retrieved batch=", retrieved_batch)
 # just assert that we retrieved a non None batch