A key to the vertebrates

A key names the class of a vertebrate from the chambers of its heart and its skin. It has a mistake: it calls the crocodile a mammal. You will fix the key, list the warm-blooded animals, and count the cold-blooded ones. Then the program draws the chambers of each heart.

The idea. Two classes have four chambers, and so does the crocodile, a reptile. With four chambers, the skin must decide: feathers, hair or scales.

Your tasks.

1. Fix vertebrate_class, so that four chambers with scales give Reptilia.
2. Set warm to the names of the warm-blooded animals (birds and mammals), in the order of the list.
3. Set cold_count to the number of cold-blooded animals.