A family tree is a map of relationships between people in a family.

Family Tree Rules:

No Time Travel Paradoxes - No one will be their own parent, child, grandparent, grandchild, etc. A person will exist in a single "generation" only.
A person can have at most two parents. They can have one or zero parents, if their parents aren't known for instance. Their parents cannot be the same person.
A person can have an arbitrary number of children, probably less than 1,000.

Required:
You must implement the following two class:
a. classPerson
b. fromperson import person