class Solution:
    def peakIndexInMountainArray(self, A):
        # return the peak of the mountain... i.e Where the array starts going down in value
        last = -1
        for ind, n in enumerate(A):
            if n < last:
                return ind - 1
            last = n

        # This should never happen
        return -1

s = Solution()
print("Expected: 1")
print("Got:", s.peakIndexInMountainArray([0, 2, 1, 0]))