diff --git a/furiosa/models/vision/resnet50/__init__.py b/furiosa/models/vision/resnet50/__init__.py
index d75dd6af..57969994 100644
--- a/furiosa/models/vision/resnet50/__init__.py
+++ b/furiosa/models/vision/resnet50/__init__.py
@@ -41,7 +41,7 @@ def __call__(
         """
         # https://github.com/mlcommons/inference/blob/af7f5a0b856402b9f461002cfcad116736a8f8af/vision/classification_and_detection/python/main.py#L37-L39
         # https://github.com/mlcommons/inference/blob/af7f5a0b856402b9f461002cfcad116736a8f8af/vision/classification_and_detection/python/dataset.py#L168-L184
-        if type(image) == str:
+        if isinstance(image, str):
             image = cv2.imread(image)
             if image is None:
                 raise FileNotFoundError(image)
diff --git a/furiosa/models/vision/ssd_mobilenet/__init__.py b/furiosa/models/vision/ssd_mobilenet/__init__.py
index 37c15611..d6e3c1ce 100644
--- a/furiosa/models/vision/ssd_mobilenet/__init__.py
+++ b/furiosa/models/vision/ssd_mobilenet/__init__.py
@@ -178,7 +178,7 @@ def __call__(
         if isinstance(images, str):
             images = [images]
         for image in images:
-            if type(image) == str:
+            if isinstance(image, str):
                 image = cv2.imread(image)
                 if image is None:
                     raise FileNotFoundError(image)
diff --git a/furiosa/models/vision/ssd_resnet34/__init__.py b/furiosa/models/vision/ssd_resnet34/__init__.py
index 5265756f..4792e13c 100644
--- a/furiosa/models/vision/ssd_resnet34/__init__.py
+++ b/furiosa/models/vision/ssd_resnet34/__init__.py
@@ -285,7 +285,7 @@ def __call__(
         if isinstance(images, str):
             images = [images]
         for image in images:
-            if type(image) == str:
+            if isinstance(image, str):
                 image = cv2.imread(image)
                 if image is None:
                     raise FileNotFoundError(image)
diff --git a/furiosa/models/vision/yolov5/core.py b/furiosa/models/vision/yolov5/core.py
index b8138e8f..07f66829 100644
--- a/furiosa/models/vision/yolov5/core.py
+++ b/furiosa/models/vision/yolov5/core.py
@@ -125,7 +125,7 @@ def __call__(
         if isinstance(images, str):
             images = [images]
         for img in images:
-            if type(img) == str:
+            if isinstance(img, str):
                 img = cv2.imread(img)
                 if img is None:
                     raise FileNotFoundError(img)