Which police forces operate in both counties that are located in the East and in the West?
return counties ;return #1 that are located in   East ;return #1 that are located in   West ;return police forces ;return #4 that operate in   #2 ;return #4 that operate in   #3 ;return #4 of both #5 and  #6
['select', 'filter', 'filter', 'select', 'filter', 'filter', 'intersection']