Continue with the ancestor trees (people refer to mother/father) from class.
Write a function count-name that consumes a name
and a family tree and produces the number of people in the family that
have the given name.
Write a function mother-known? that consumes a name
and a family tree and produces a boolean indicating whether the named
person's mother is known (is a person, rather than 'unknown).
Write a function update-mother that consumes a
person's name, person-struct for their mother, and a family tree and
returns a family tree in which the named person has the given person
structure as their mother (you may assume that the person's mother was
unknown in the original tree if you wish).
Write a function add-mother that consumes a
person's name, name, birth year and eye color for that person's mother
and a family tree and produces a family tree in which the named person
has a mother with the given data. Use update-mother as a
helper.