Revert "Merge branch 'pr/1'"

This reverts commit 5cbb4ba33304cdbb3df8a0431685c716d769def3, reversing
changes made to 08af742bbc1d30f664d085d7c5432da7ef85d5fc.
Revert "update doc"

This reverts commit 08af742bbc1d30f664d085d7c5432da7ef85d5fc.