color_list_1 = set(["White", "Black", "Red"])
color_list_2 = set(["Red", "Green"])
a = color_list_1 - color_list_2
print(a)
color_list_1 = set(["White", "Black", "Red"])
color_list_2 = set(["Red", "Green"])
a = color_list_1 - color_list_2
print(a)