The disease finder

A dictionary holds the kind of pathogen and the way of spreading for ten diseases. You will look up a disease, list the diseases of one route, and count the diseases of each kind.

The idea. A dictionary maps a name to a value. Use the disease name as the key.

Your tasks.

1. Finish kind_of. It gives the kind of pathogen of a disease.
2. Finish diseases_by. It gives the sorted list of diseases that spread by a route.
3. Finish count_kinds. It gives a dictionary that counts the diseases of each kind.