我这为什么出不来结果呀，帮解释一下

basket=['apple',' banana',' apple','orange']；
fruit=set (basket)；
fruit2 = set(['apple','melo'])；
len(fruit/fruit2)

。。。SET除以SET?
Jupyter环境？

basket=['apple',' banana',' apple','orange']
fruit=set (basket)
fruit2 = set(['apple','melo'])
print(len(fruit)/len(fruit2))
#print(len(fruit/fruit2))