CSV模块语法

Question

所以我制作了一个程序，用Python演示了CSV模块。出于某种原因，我在print("You spent"...)之后出现语法错误，为什么会这样？

#!/usr/bin/env python
import csv
total = 0
priciest = ('',0,0,0)
r = csv.reader(open('purchases.csv'))
for row in r:
    cost = float(row[1]) * float(row[2])
    total += cost
    if cost == priciest[3]:
        priciest = row + [cost]
print("You spent", total)
print("Your priciest purchase was", priciest[1], priciest[0], "at a total cost of", priciest[3])