Minor fixes

yolort/models/transform.py

@@ -161,13 +161,12 @@ def forward(
         Perform letterboxing transformation.
 
         Args:
-            images (List[Tensor]): Images to be processed. In general the input type of images
-                is a list of `Tensors`, except for two different types of scenarios:
-                - For the dataloader in training and evaluation, the `images` will be a 4-dim
-                    Tensor in that case.
-                - For shape inference when exporting ONNX models.
-            targets (List[Dict[Tensor]], optional): ground-truth boxes present in the image.
-                Default: None
+            images (List[Tensor]): Images to be processed. In general the type of images is a list
+                of 3-dim `Tensors`, except for the dataloader in training and evaluation, the `images`
+                will be a 4-dim `Tensor` in that case. Check out the belows link for more details:
+                https://github.com/zhiqwang/yolov5-rt-stack/pull/308#pullrequestreview-878689796
+            targets (List[Dict[Tensor]], optional): ground-truth boxes present in the image for
+                training. Default: None
 
         Returns:
             result (List[BoxList] or Dict[Tensor]): the output from the model.