diff --git a/yolov5/detect.py b/yolov5/detect.py
index 153f2c2..ed1e6b4 100644
--- a/yolov5/detect.py
+++ b/yolov5/detect.py
@@ -260,8 +260,9 @@ def parse_opt():
     return opt
 
 
-def main():
-    opt = parse_opt()
+def main(opt=None):
+    if opt is None:
+        opt = parse_opt()
     check_requirements(exclude=('tensorboard', 'thop'))
     run(**vars(opt))