If each image contains exactly one dark flute with metal keys.
return images ;return flutes in  #1 ;return #2 that are dark ;return keys of #3 ;return #3 where  #4 are metal ;return number of  #5 for each  #1 ;return #1 where  #6 is equal to  one ;return number of  #7 ;return number of  #1 ;return if  #8 is equal to  #9
['select', 'project', 'filter', 'project', 'comparative', 'group', 'comparative', 'aggregate', 'aggregate', 'boolean']