Find first and Last position of Element in sorted array

class Solution {
public:
    vector<int> searchRange(vector<int>& nums, int target) {
        vector<int> ans;
        vector<int>::iterator l, r;
        l=lower_bound(nums.begin(),nums.end(),target);
        r=upper_bound(nums.begin(),nums.end(),target);
        if(l==nums.end() || nums[l-nums.begin()]!=target || l==r){
            ans.push_back(-1);ans.push_back(-1); return ans;
        }
        ans.push_back(l-nums.begin());
        ans.push_back(r-nums.begin()-1);
        return ans;
    }
};

#Python
from typing import List

def first_element(nums, l, r, target):
    if l <= r:
        mid = (l + r) // 2
        if nums[mid] == target:
            if mid == 0 or nums[mid - 1] != target:
                return mid
            return first_element(nums, l, mid - 1, target)
        elif nums[mid] < target:
            return first_element(nums, mid + 1, r, target)
        else:
            return first_element(nums, l, mid - 1, target)
    return -1

def last_element(nums, l, r, target):
    if l <= r:
        mid = (l + r) // 2
        if nums[mid] == target:
            if mid == r or nums[mid + 1] != target:
                return mid
            return last_element(nums, mid + 1, r, target)
        elif nums[mid] < target:
            return last_element(nums, mid + 1, r, target)
        else:
            return last_element(nums, l, mid - 1, target)
    return -1

class Solution:
    def searchRange(self, nums: List[int], target: int) -> List[int]:
        if not nums:
            return [-1, -1]
        a = first_element(nums, 0, len(nums) - 1, target)
        if a == -1:
            return [-1, -1]
        b = last_element(nums, 0, len(nums) - 1, target)
        return [a, b]