Luke Skywalker has family and friends. Help him remind them who is who. Given a string with a name, return the relation of that person to Luke.
| Person | Relation |
|---|---|
| Darth Vader | father |
| Leia | sister |
| Han | brother in law |
| R2D2 | droid |
relation_to_luke("Darth Vader") ➞ "Luke, I am your father."
relation_to_luke("Leia") ➞ "Luke, I am your sister."
relation_to_luke("Han") ➞ "Luke, I am your brother in law."
N/A