852. Peak Index in a Mountain Array Find the single peak in given mountain array

class Solution:
    def peakIndexInMountainArray(self, a: List[int]) -> int:
        l,r=0,len(a)-1
        n=len(a)
        while l<r:#After converging answer will be a[l] or a[r]
            m=(l+r)>>1#compare with right one
            if a[m]<a[m+1]:#Possibility of Peak here with m+1 hence l=m+1
                l=m+1
            else:
                r=m
        return l