Was a film editor that was employed by M2 and M3 and was employed by M4 a screenwriter
SELECT count(*) WHERE {
?x0 a ns:film.editor .
?x0 a ns:film.writer .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M3 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M4
}