From: @jiangzg001
Reviewed-by: @liangchenghui
Signed-off-by: @liangchenghui

From: @yuan_shen_zhou
Reviewed-by: 
Signed-off-by:

From: @lianliguang
Reviewed-by: @zh_qh,@zh_qh,@chujinjin
Signed-off-by: @zh_qh,@zh_qh

From: @jiangzg001
Reviewed-by: @liangchenghui,@wuxuejian
Signed-off-by: @liangchenghui

A minor change in sigmoidGradGrad operation (non-functional change).

From: @liangchenghui
Reviewed-by: @c_34,@wuxuejian
Signed-off-by: @wuxuejian

check input dims for nn.LSTM.

From: @david-he91
Reviewed-by: @liangchenghui,@linqingke
Signed-off-by: @liangchenghui

From: @david-he91
Reviewed-by: 
Signed-off-by:

From: @jiangzg001
Reviewed-by: 
Signed-off-by:

Merge pull request !4706 from Peilin/smoothL1Loss-fix

fix pylint

changed doc and code for SmoothL1Loss to be same a dchip. fixed grad kernel

fix ci

Merge pull request !3577 from fangzehua/many_grad_ops

Merge pull request !3746 from baihuawei/loss