If there are two people on the sled being pulled by at least four dogs.
return sled ;return dogs ;return people ;return #3 that are on #1 ;return number of  #4 ;return if  #5 is equal to  two ;return #2 that #1 is pulled by ;return number of  #7 ;return if  #8 is at least four ;return if  both  #6 and #9 are true
['select', 'select', 'select', 'filter', 'aggregate', 'boolean', 'filter', 'aggregate', 'boolean', 'boolean']