Find the number of visitors who did not visit any museum opened after 2010.
SELECT count(*) FROM visitor WHERE id NOT IN (SELECT t2.visitor_id FROM museum AS t1 JOIN visit AS t2 ON t1.Museum_ID  =  t2.Museum_ID WHERE t1.open_year  >  2010)
SELECT count(*) FROM visitor WHERE id NOT IN (SELECT t2.visitor_id FROM museum AS t1 JOIN visit AS t2 ON t1.Museum_ID  =  t2.Museum_ID WHERE t1.open_year  >  2010)
[{'count(*)': 3}]