If one pair of pants is worn by a human and the other is by itself.
return pair of pants ;return human ;return #1 worn by  #2 ;return #1 besides  #3 ;return the  number of  #3 ;return the  number of  #4 ;return if  #5 is equal to  one ;return if  #6 is equal to  one ;return if  both  #7 and #8 is true
['select', 'select', 'filter', 'discard', 'aggregate', 'aggregate', 'boolean', 'boolean', 'boolean']