Single Element in a Sorted Array

class Solution(object):
    def singleNonDuplicate(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        beg = 0
        end = len(nums) - 1
        mid = 2*((end-beg)//4) + beg
        while(beg < end):
            if nums[mid] != nums[mid + 1]:
                end = mid
            else:
                beg = mid + 2
            mid = 2*((end-beg)//4) + beg

        return nums[beg]