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

From: @lijiaqi0612
Reviewed-by: 
Signed-off-by:

From: @wangrao124
Reviewed-by: @kingxian,@liangchenghui
Signed-off-by: @kingxian

From: @gzhcv
Reviewed-by: @yelihua,@ouwenchang
Signed-off-by: @ouwenchang

From: @zichun_ye
Reviewed-by: @sunnybeike,@wang_zi_dong
Signed-off-by: @sunnybeike

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

From: @xsmq
Reviewed-by: @ljl0711,@zhoufeng54
Signed-off-by: @zhoufeng54

From: @lizhenglong1992
Reviewed-by: @heleiwang,@liucunwei
Signed-off-by: @liucunwei

From: @shenwei41
Reviewed-by: 
Signed-off-by:

From: @hwhewei
Reviewed-by: @zh_qh,@ginfung
Signed-off-by: @zh_qh

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

From: @TFbunny
Reviewed-by: @robingrosman
Signed-off-by: @robingrosman

From: @TFbunny
Reviewed-by: @robingrosman,@tom__chen
Signed-off-by: @robingrosman

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

From: @zhoufeng54
Reviewed-by: 
Signed-off-by:

This reverts commit 141c39b71c.

From: @zhoufeng54
Reviewed-by: @xu-yfei,@kisnwang
Signed-off-by: @xu-yfei

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

From: @yeyunpeng2020
Reviewed-by: @hangangqiang,@zhang_xue_tong
Signed-off-by: @hangangqiang

From: @jachua
Reviewed-by: @xsmq,@liangchenghui
Signed-off-by: @liangchenghui

From: @jjfeing
Reviewed-by: @kisnwang,@zhoufeng54
Signed-off-by: @zhoufeng54

From: @Margaret_wangrui
Reviewed-by: @hwhewei,@zh_qh
Signed-off-by: @zh_qh

From: @liyong126
Reviewed-by: @savoygll,@heleiwang,@liucunwei
Signed-off-by: @savoygll,@liucunwei

From: @zyhstack
Reviewed-by: @ouwenchang,@lixiaohui33
Signed-off-by: @lixiaohui33

From: @wangshuide2020
Reviewed-by: @liangchenghui,@ljl0711
Signed-off-by: @liangchenghui

Changed the expander to class, and used the class name to identify the operator.
Moved the original op logic into the `_expand` function; added a `_check` function to check op inputs.

Use decorator to register the whitelist formats that operator supports,
and the decorator will change the `_check` function to check the formats.

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

From: @yeyunpeng2020
Reviewed-by: 
Signed-off-by:

From: @zhupuxu
Reviewed-by: @jjfeing
Signed-off-by:

From: @changzherui
Reviewed-by: @kingxian,@zhoufeng54
Signed-off-by: @kingxian

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

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

From: @wangrao124
Reviewed-by: @wuxuejian,@kisnwang
Signed-off-by: @wuxuejian

Signed-off-by: zhoufeng <zhoufeng54@huawei.com>

From: @lzkcode
Reviewed-by: @zhang_xue_tong,@zhanghaibo5
Signed-off-by: @zhang_xue_tong