python leetcode 162. Find Peak Element

class Solution(object):
    def findPeakElement(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        if not nums:
            return -1
        for i in range(len(nums)):
            if i+1<len(nums) and nums[i]>nums[i+1]:
                return i
            
        return len(nums)-1