human
I found an interesting problem on https://leetcode.com/problems/unique-number-of-occurrences/:
Given an array of integers arr, write a function that returns true if and only if the number of occurrences of each value in the array is unique.
 
Example 1:
Input: arr = [1,2,2,1,1,3]
Output: true
Explanation: The value 1 has 3 occurrences, 2 has 2 and 3 has 1. No two values have the same number of occurrences.
Example 2:
Input: arr = [1,2]
Output: false

Example 3:
Input: arr = [-3,0,1,-3,1,1,1,-3,10,0]
Output: true

 
Constraints:

1 <= arr.length <= 1000
-1000 <= arr[i] <= 1000

I tried it in Python, but could not do it. Can you solve it?
assistant
#Here is the Python code you requested.

class Solution:
    def uniqueOccurrences(self, arr: List[int]) -> bool:
        count = Counter(arr)
        s = set()
        
        for k,v in list(count.items()):
            if v in s:
                return False
            else:
                s.add(v)
        return True