!8877 fix api comment with none optional parameter

From: @jonyguo
Reviewed-by: @pandoublefeng,@liucunwei
Signed-off-by: @liucunwei

mindspore/dataset/transforms/c_transforms.py

@@ -338,7 +338,7 @@ class Compose(cde.ComposeOp):
         >>> import mindspore.dataset.transforms.c_transforms as c_transforms
         >>> import mindspore.dataset.vision.c_transforms as c_vision
         >>>
-        >>> compose = c_transforms.Compose([c_vision.Decode(), c_vision.RandomCrop()])
+        >>> compose = c_transforms.Compose([c_vision.Decode(), c_vision.RandomCrop(512)])
         >>> data1 = data1.map(operations=compose)
     """
 
@@ -359,7 +359,7 @@ class RandomApply(cde.RandomApplyOp):
         >>> import mindspore.dataset.transforms.c_transforms as c_transforms
         >>> import mindspore.dataset.vision.c_transforms as c_vision
         >>>
-        >>> rand_apply = c_transforms.RandomApply([c_vision.RandomCrop()])
+        >>> rand_apply = c_transforms.RandomApply([c_vision.RandomCrop(512)])
         >>> data1 = data1.map(operations=rand_apply)
     """
 
@@ -379,7 +379,7 @@ class RandomChoice(cde.RandomChoiceOp):
         >>> import mindspore.dataset.transforms.c_transforms as c_transforms
         >>> import mindspore.dataset.vision.c_transforms as c_vision
         >>>
-        >>> rand_choice = c_transforms.RandomChoice([c_vision.CenterCrop(), c_vision.RandomCrop()])
+        >>> rand_choice = c_transforms.RandomChoice([c_vision.CenterCrop(50), c_vision.RandomCrop(512)])
         >>> data1 = data1.map(operations=rand_choice)
     """
 

mindspore/dataset/vision/c_transforms.py

@@ -560,7 +560,7 @@ class RandomPosterize(cde.RandomPosterizeOp):
             Bits values must be in range of [1,8], and include at
             least one integer value in the given range. It must be in
             (min, max) or integer format. If min=max, then it is a single fixed
-            magnitude operation (default=[8, 8]).
+            magnitude operation (default=(8, 8)).
 
     Examples:
         >>> import mindspore.dataset.vision.c_transforms as c_vision
@@ -1062,7 +1062,7 @@ class HWC2CHW(cde.ChannelSwapOp):
     Examples:
         >>> import mindspore.dataset.vision.c_transforms as c_vision
         >>>
-        >>> transforms_list = [c_vision.Decode(), c_vision.RandomHorizontalFlip(0.75), c_vision.RandomCrop(),
+        >>> transforms_list = [c_vision.Decode(), c_vision.RandomHorizontalFlip(0.75), c_vision.RandomCrop(512),
         >>>     c_vision.HWC2CHW()]
         >>> data1 = data1.map(operations=transforms_list, input_columns=["image"])
     """