[kovidgoyal]

Those functions still exist, though note that it is get_metadata.

calibre-debug -c "from calibre.library import db; db = db(); print db.series, db.get_metadata"                                                                                                      
<bound method LibraryDatabase.func of <calibre.db.legacy.LibraryDatabase object at 0x7f856b61fc10>> <bound method LibraryDatabase.get_metadata of <calibre.db.legacy.LibraryDatabase object at 0x7f856b61fc10>>