The in and not in operators can also check membership in a set or frozen set.

Like the more usual relational operators, in and not in can be used in compound relational expressions. For example, 'a' in 'alpha' in {'alpha', 'bravo'} is true because 'a' in 'alpha' and 'alpha' in {'alpha', 'bravo'} are both true.

Fill in the placeholders so that the actual outputs match the expected outputs.