Revert "Revert "7 book""

This reverts commit 58c10a8408ad7fe7a54f6c03a98950a694fe2bf7.
Revert "Revert "9 book""

This reverts commit 85a6d45c6b13e98b035428729df63c95649e423f.
Revert "12 book"

This reverts commit 9baad4aafcba2821cd9474836d831165d01de757.
Revert "Revert "12 book""

This reverts commit f3cb10ff1449c65d4248ee45e004b3ea9bc996bb.
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