implementation of libary as well as staff timetable
- arrive personName time: the time that a person arrived at the library
- exit personName time: the time that a person leave the library
- isInLib personName: check whether the person in in the library
- returnBook personName bookName: return the book which lended by personName
- totalTimeInLib personName startTime endTime: the total time a person been in the library
- addNewBook bookName count : add new book to library
- shouldBring bookName personName : bookName has lended by personName
- allPersonCurrentBook personName : all books that have lended by people
- allPersonHave bookName : all people have lended the specefic book