two pointer approach to solve array sum pair problem

#condition is that array needs to be sorted to use two pointer approach 
def pairsum(arr,target):
        i=0
        j=len(arr)-1 
        while i<j:
                if arr[i]+ arr[j]<target: 
                        i=i+1
                elif arr[i] + arr[j]>target: 
                        j=j-1
                else: 
                        return arr[i],arr[j]