1) use a special value.
Merge branch 'master' of https://github.com/sxsfxx/PythonStudy
Merge branch 'master' of https://github.com/sxsfxx/PythonStudy
Merge branch 'master' of https://github.com/sxsfxx/PythonStudy
1) rename.
Merge branch 'master' of https://github.com/sxsfxx/PythonStudy
1) problem 53.
Merge branch 'master' of https://github.com/sxsfxx/PythonStudy
1) rename, add notes.
1) AGE demo.
1) new project MyBookList.
1) now, this toy can emulate to inquiry.