I write a python code like following, but the output is None. Anyone know the reason?

class Solution:

```
# @param {integer[]} nums
# @return {integer}
def findMin(self, nums):
if len(nums) == 1 or nums[0] < nums[-1]:
return nums[0]
if len(nums) == 2:
return min(nums)
mid = len(nums)/2
if nums[mid] < nums[-1]:
self.findMin(nums[:mid+1])
else:
self.findMin(nums[mid:])
```

s = Solution()

print s.findMin([3,1,2])