human
Solve in Python:
Given an array of integers arr of even length n and an integer k.
We want to divide the array into exactly n / 2 pairs such that the sum of each pair is divisible by k.
Return True If you can find a way to do that or False otherwise.
 
Example 1:
Input: arr = [1,2,3,4,5,10,6,7,8,9], k = 5
Output: true
Explanation: Pairs are (1,9),(2,8),(3,7),(4,6) and (5,10).

Example 2:
Input: arr = [1,2,3,4,5,6], k = 7
Output: true
Explanation: Pairs are (1,6),(2,5) and(3,4).

Example 3:
Input: arr = [1,2,3,4,5,6], k = 10
Output: false
Explanation: You can try all possible pairs to see that there is no way to divide arr into 3 pairs each with sum divisible by 10.

Example 4:
Input: arr = [-10,10], k = 2
Output: true

Example 5:
Input: arr = [-1,1,-2,2,-3,3,-4,4], k = 3
Output: true

 
Constraints:

arr.length == n
1 <= n <= 10^5
n is even.
-10^9 <= arr[i] <= 10^9
1 <= k <= 10^5

Give me a Python code to find a way to do that or False otherwise?
assistant
#Here is Python code to find a way to do that or False otherwise.

class Solution:
    def canArrange(self, arr: List[int], k: int) -> bool:
        bag = {}
        for i in arr:
            if i < 0:
                i += ((-i) // k +1) * k
                
            r = i % k
            

            if r != 0:
                if k-r not in bag:
                    if r not in bag:
                        bag[r] = 0
                    bag[r] += 1
                else:
                    bag[k-r] -= 1
                    if bag[k-r] == 0:
                        del bag[k-r]
            else:
                if 0 in bag:
                    del bag[0]
                else:
                    bag[0]= 1
        return len(bag) == 0