diff --git a/api/onnx_web/diffusers/pipelines/upscale.py b/api/onnx_web/diffusers/pipelines/upscale.py
index fc0e477b..e9df3a5f 100644
--- a/api/onnx_web/diffusers/pipelines/upscale.py
+++ b/api/onnx_web/diffusers/pipelines/upscale.py
@@ -55,11 +55,7 @@ class FakeConfig:
     scaling_factor: float
 
     def __init__(self) -> None:
-        self.block_out_channels = [
-            128,
-            256,
-            512
-        ]
+        self.block_out_channels = [128, 256, 512]
         self.scaling_factor = 0.08333
 
 
diff --git a/api/onnx_web/server/api.py b/api/onnx_web/server/api.py
index bbd5f038..a9162f0f 100644
--- a/api/onnx_web/server/api.py
+++ b/api/onnx_web/server/api.py
@@ -8,6 +8,7 @@ from jsonschema import validate
 from PIL import Image
 
 from ..chain import CHAIN_STAGES, ChainPipeline
+from ..chain.result import StageResult
 from ..diffusers.load import get_available_pipelines, get_pipeline_schedulers
 from ..diffusers.run import (
     run_blend_pipeline,
@@ -472,7 +473,7 @@ def chain(server: ServerContext, pool: DevicePoolExecutor):
         pipeline,
         server,
         base_params,
-        [],
+        StageResult.empty(),
         output=output,
         size=base_size,
         needs_device=device,