Sort Array by Increasing Frequency

1class Solution:
2    def frequencySort(self, nums: List[int]) -> List[int]:
3        freqs = collections.Counter()
4        for num in nums:
5            freqs[num*-1] += 1
6        
7        sorted_freq = sorted(freqs.items(), key = lambda x: (x[1],x[0]))
8        res = []
9        for key,value in sorted_freq:
10            for i in range(value):
11                res.append(key * -1)
12        return res