diff --git a/test/test_image_utils.py b/test/test_image_utils.py
index b429f271..3b6c3301 100644
--- a/test/test_image_utils.py
+++ b/test/test_image_utils.py
@@ -3,7 +3,8 @@
 
 import torch
 
-from yolort.utils.image_utils import box_cxcywh_to_xyxy, letterbox, scale_coords
+from yolort.utils.image_utils import box_cxcywh_to_xyxy
+from yolort.ultralytics import letterbox, scale_coords
 
 
 def test_letterbox():
@@ -16,11 +17,11 @@ def test_box_cxcywh_to_xyxy():
     box_cxcywh = np.asarray([[50, 50, 100, 100],
                             [0, 0, 0, 0],
                             [20, 25, 20, 20],
-                            [58, 65, 70, 60]], dtype=np.float32)
+                            [58, 65, 70, 60]], dtype=np.float)
     exp_xyxy = np.asarray([[0, 0, 100, 100],
                            [0, 0, 0, 0],
                            [10, 15, 30, 35],
-                           [23, 35, 93, 95]], dtype=np.float32)
+                           [23, 35, 93, 95]], dtype=np.float)
 
     box_xyxy = box_cxcywh_to_xyxy(box_cxcywh)
     assert exp_xyxy.shape == (4, 4)
@@ -38,6 +39,6 @@ def test_scale_coords():
                                [7.9250, 16.6875, 30.1750, 38.9375],
                                [19.05, 38.9375, 96.9250, 105.6875]], dtype=torch.float)
 
-    box_coords_scaled = scale_coords(box_tensor, (160, 128), (178, 136))
+    box_coords_scaled = scale_coords((160, 128), box_tensor, (178, 136))
     assert tuple(box_coords_scaled.shape) == (4, 4)
     torch.testing.assert_close(box_coords_scaled, exp_coords)
diff --git a/yolort/ultralytics/__init__.py b/yolort/ultralytics/__init__.py
index 3cef3ce2..a1ce8a83 100644
--- a/yolort/ultralytics/__init__.py
+++ b/yolort/ultralytics/__init__.py
@@ -1,4 +1,4 @@
 from .models.common import *
 from .models.yolo import *
-from .helper import load_yolov5_model
+from .helper import add_yolov5_context
 from .hubconf import yolov5s
diff --git a/yolort/ultralytics/helper.py b/yolort/ultralytics/helper.py
index ec98427f..93651e3e 100644
--- a/yolort/ultralytics/helper.py
+++ b/yolort/ultralytics/helper.py
@@ -12,7 +12,7 @@
 
 
 @contextlib.contextmanager
-def load_yolov5_model():
+def add_yolov5_context():
     """
     Temporarily add yolov5 folder to `sys.path`. Modified from:
     https://github.com/fcakyon/yolov5-pip/blob/0d03de6/yolov5/utils/general.py#L739-L754
@@ -38,7 +38,6 @@ def attempt_load(weights, map_location=None, inplace=True, fuse=True):
         else:
             model.append(ckpt['ema' if ckpt.get('ema') else 'model'].float().eval())  # without layer fuse
 
-
     # Compatibility updates
     for m in model.modules():
         if type(m) in [nn.Hardswish, nn.LeakyReLU, nn.ReLU, nn.ReLU6, nn.SiLU, Detect, Model]:
@@ -52,5 +51,6 @@ def attempt_load(weights, map_location=None, inplace=True, fuse=True):
         print(f'Ensemble created with {weights}\n')
         for k in ['names']:
             setattr(model, k, getattr(model[-1], k))
-        model.stride = model[torch.argmax(torch.tensor([m.stride.max() for m in model])).int()].stride  # max stride
+        # max stride
+        model.stride = model[torch.argmax(torch.tensor([m.stride.max() for m in model])).int()].stride
         return model  # return ensemble