If one of the bookshelves has wooden cabinet doors at the bottom.
return bookshelves ;return bottom of #1 ;return cabinet doors ;return #3 that are wooden ;return #1 where  #2 has #4 ;return number of  #5 ;return if  #6 is equal to  one
['select', 'project', 'select', 'filter', 'comparative', 'aggregate', 'boolean']