diff --git a/diffusion/inference/inference_model.py b/diffusion/inference/inference_model.py
index 8dbbd306..c4d95b83 100644
--- a/diffusion/inference/inference_model.py
+++ b/diffusion/inference/inference_model.py
@@ -5,7 +5,7 @@
 
 import base64
 import io
-from typing import Any, Dict, List, Optional
+from typing import Any, Dict, List
 
 import torch
 from composer.utils.file_helpers import get_file