What is average lesson price taught by staff with first name as Janessa and last name as Sawayn?
SELECT avg(price) FROM Lessons AS T1 JOIN Staff AS T2 ON T1.staff_id = T2.staff_id WHERE T2.first_name = "Janessa" AND T2.last_name = "Sawayn";
SELECT avg(price) FROM Lessons AS T1 JOIN Staff AS T2 ON T1.staff_id = T2.staff_id WHERE T2.first_name = "Janessa" AND T2.last_name = "Sawayn";
[{'avg(price)': 306.0}]