Lab: the contact book

A dictionary plus a function

Build the smallest useful app: a phone book you can look names up in.

Build it yourself — nothing is given this time.

1. contacts — a dictionary with these three entries, added in this order: Ada → 555-0101, Grace → 555-0102, Katherine → 555-0103
2. a function lookup(name) that returns the phone number, or Unknown when the name is not in the book
3. a loop that prints every contact, one per line, as Ada: 555-0101

Then print the result of lookup("Ada") and the result of lookup("Alan").