If there is an empty drum open so the inside is viewable
return drum ;return #1 that is empty ;return #2 that is open ;return inside of #3 ;return #3 where  #4 is viewable ;return number of  #5 ;return if  #6 is at least one
['select', 'filter', 'filter', 'project', 'comparative', 'aggregate', 'boolean']