SQLite database backup

For backup of SQLite database, I went through http://ift.tt/1FB4i7q I came to know that there is one python wrapper over these SQLite online backup APIs.So, I went through http://ift.tt/1AqtfxY Here are some doubts that I have about sqlitebck(python package)

1. I checked out the code in tests, it shows db is copied from :memory: to file and vice versa using sqlitebck.copy(:memory:,dbfile), I am confused about ":memory:" and its use.


2. Instead from memory, can I copy one database file to other database file like sqlitebck(dbfile1, dbfile2). so that dbfile2 will be the backup of dbfile1?