Go Fish

Write a program to let the user play Go Fish against a computer opponent. Use the following rules:

Each player is dealt nine cards to start with.
On their turn, a player asks their opponent for a given rank (such as threes or kings). A player must already have at least one card of a given rank to ask for more.
- If the opponent has any cards of the named rank, they must hand over all such cards, and the requester can ask again.
- If the opponent has no cards of the named rank, the requester draws a card and ends their turn.
A book is a collection of every card of a given rank. Whenever a player completes a book, they may remove it from their hand.
If at any time a player's hand is empty, they may immediately draw a new card, so long as any new cards remain in the deck.
The game ends when every book is complete. The player with the most books wins.

The game's AI need not be terribly smart, but it should use at least some strategy. That is, it shouldn't choose legal moves entirely at random.

You may want to use code from Playing Cards.