```
class Solution(object):
def multiply(self, num1, num2):
"""
:type num1: str
:type num2: str
:rtype: str
"""
l1 = map(int, num1)[::-1]
l2 = map(int, num2)[::-1]
sum = 0
for i, m in enumerate(l1):
for j, n in enumerate(l2):
sum += m * n * 10 ** (i + j)
return str(sum)
```