Repository: Project-MONAI/MONAI

Issue:
minior comment error
![image](https://user-images.githubusercontent.com/11666931/87648023-32ca0e00-c782-11ea-98fa-dcb1c3098c35.png)
![image](https://user-images.githubusercontent.com/11666931/87648182-42495700-c782-11ea-8df5-c89fddb5bc83.png)



Discussion:

Resolving patch:
diff --git a/monai/transforms/croppad/array.py b/monai/transforms/croppad/array.py
--- a/monai/transforms/croppad/array.py
+++ b/monai/transforms/croppad/array.py
@@ -411,10 +411,10 @@ class RandCropByPosNegLabel(Randomizable, Transform):
             If its components have non-positive values, the corresponding size of `label` will be used.
         label: the label image that is used for finding foreground/background, if None, must set at
             `self.__call__`.  Non-zero indicates foreground, zero indicates background.
-        pos: used to calculate the ratio ``pos / (pos + neg)`` for the probability to pick a
-            foreground voxel as a center rather than a background voxel.
-        neg: used to calculate the ratio ``pos / (pos + neg)`` for the probability to pick a
-            foreground voxel as a center rather than a background voxel.
+        pos: used with `neg` together to calculate the ratio ``pos / (pos + neg)`` for the probability
+            to pick a foreground voxel as a center rather than a background voxel.
+        neg: used with `pos` together to calculate the ratio ``pos / (pos + neg)`` for the probability
+            to pick a foreground voxel as a center rather than a background voxel.
         num_samples: number of samples (crop regions) to take in each list.
         image: optional image data to help select valid area, can be same as `img` or another image array.
             if not None, use ``label == 0 & image > image_threshold`` to select the negative
diff --git a/monai/transforms/croppad/dictionary.py b/monai/transforms/croppad/dictionary.py
--- a/monai/transforms/croppad/dictionary.py
+++ b/monai/transforms/croppad/dictionary.py
@@ -357,10 +357,10 @@ class RandCropByPosNegLabeld(Randomizable, MapTransform):
         label_key: name of key for label image, this will be used for finding foreground/background.
         spatial_size: the spatial size of the crop region e.g. [224, 224, 128].
             If its components have non-positive values, the corresponding size of `data[label_key]` will be used.
-        pos: used to calculate the ratio ``pos / (pos + neg)`` for the probability to pick a
-            foreground voxel as a center rather than a background voxel.
-        neg: used to calculate the ratio ``pos / (pos + neg)`` for the probability to pick a
-            foreground voxel as a center rather than a background voxel.
+        pos: used with `neg` together to calculate the ratio ``pos / (pos + neg)`` for the probability
+            to pick a foreground voxel as a center rather than a background voxel.
+        neg: used with `pos` together to calculate the ratio ``pos / (pos + neg)`` for the probability
+            to pick a foreground voxel as a center rather than a background voxel.
         num_samples: number of samples (crop regions) to take in each list.
         image_key: if image_key is not None, use ``label == 0 & image > image_threshold`` to select
             the negative sample(background) center. so the crop center will only exist on valid image area.


Test patch: