Which cities have 2 to 4 parks?
return cities ;return parks of #1 ;return number of  #2 for each #1 ;return #1 where #3 is  at least 2 ;return #1 where #3 is  at most 4 ;return #1 in both #4 and #5
['select', 'project', 'group', 'comparative', 'comparative', 'intersection']