Find the number of cartoons directed by each of the listed directors.
SELECT count(*) ,  Directed_by FROM cartoon GROUP BY Directed_by
SELECT count(*) ,  Directed_by FROM cartoon GROUP BY Directed_by
[{'count(*)': 4, 'Directed_by': 'Ben Jones'}, {'count(*)': 4, 'Directed_by': 'Brandon Vietti'}, {'count(*)': 4, 'Directed_by': 'Michael Chang'}]