"""calc.py: A simple calculator."""

import sys

def add_all(nums):
    return sum(nums)

def multiply_all(nums):
    return reduce(lambda a, b: a * b, nums)

if __name__ == '__main__':
    command = sys.argv[1]
    nums = map(float, sys.argv[2:])
    if command == 'add':
        print(add_all(nums))
    elif command == 'multiply':
        print(multiply_all(nums))

@@ -349,20 +349,117 @@
 multiply_all(nums))%0A
+    else:%0A        usage = %22calc.py %5Badd%7Cmultiply%5D NUM1 %5BNUM2 %5BNUM3 %5B...%5D%5D%5D%22%0A        print(usage)%0A

Add usage string for fallthrough cases