If there is at most 2 groups of sleigh dogs pulling a sled to the left in the snow.
return groups of sleigh dogs ;return sled ;return #1 pulling #2 to  the  left ;return the  snow ;return #3 in  #4 ;return number of  #5 ;return if  #6 is at most 2
['select', 'select', 'filter', 'select', 'filter', 'aggregate', 'boolean']