If some safety pins have letters and numbers on them.
return safety pins ;return letters ;return numbers ;return #1 that have  #2 on them ;return #1 that have  #3 on them ;return #1 in  both  #4 and #5 ;return number of  #6 ;return if  #7 is  at least two
['select', 'select', 'select', 'filter', 'filter', 'intersection', 'aggregate', 'boolean']