What is the first name of all employees who do not give any lessons?
SELECT first_name FROM Staff EXCEPT SELECT T2.first_name FROM Lessons AS T1 JOIN Staff AS T2 ON T1.staff_id  =  T2.staff_id
SELECT first_name FROM Staff EXCEPT SELECT T2.first_name FROM Lessons AS T1 JOIN Staff AS T2 ON T1.staff_id  =  T2.staff_id
[{'first_name': 'Camylle'}, {'first_name': 'Ernestina'}, {'first_name': 'Eulalia'}, {'first_name': 'Jaleel'}, {'first_name': 'Margie'}, {'first_name': 'Queenie'}]