Populating menus and adding dialogs
As part of the controller/view aspect, the menubar has a number of items whose callbacks need to be implemented still. This would be functionality such as new game and save game dialogs, file dialogs for choosing different cardsets, etc.
If working on the new game and save game dialogs don't delve into storing and cloning the game state just yet. Let the focus be on creating the prompts and windows.
Ideas for Implementation
There is a widget called tkFileDialog that may help if I remember correctly. I am pretty sure that's the way to go. Feel free to do your own research as this is fairly open-ended. The main requirement is that it must be a GUI-based implementation, no inputting of file names or directories via console. Other requirements would be basic exception-handling for invalid files,etc. but that can be dealt with when the time comes