What are the names of the characteristics of the product 'sesame' that have the characteristic type code 'Grade'?
return products ;return #1 which are  'sesame ;return characteristic type codes of  #1 ;return #3 which are  'Grade ;return #1 of  both #4 and  #2 ;return names of  characteristics of #5
['select', 'filter', 'project', 'filter', 'intersection', 'project']