This generic class represents a person in line. A person should be able to carry a parcel of any type.

Note: You may NOT create any instance variables nor instance methods that are not required.

Generic Type:

$$ T $$ the type of parcel this person carries

Variables:

$$ parcel $$ the parcel this person carries

o If we ever attempt to set its value to null, throw an IllegalArgumentException.

$$ nextPerson $$ a reference to the next person in line, which should also carry the same type of

parcel as this person