Split Array into Consecutive Subsequences

class Solution:    def isPossible(self, nums: List[int]) -> bool:        if len(nums) < 3: return False        frequency = collections.Counter(nums)        subsequence = collections.defaultdict(int)        for i in nums:            if frequency[i] == 0:                continue            frequency[i] -= 1            # option 1 - add to an existing subsequence            if subsequence[i-1] > 0:                subsequence[i-1] -= 1                subsequence[i] += 1            # option 2 - create a new subsequence             elif frequency[i+1] and frequency[i+2]:                frequency[i+1] -= 1                frequency[i+2] -= 1                subsequence[i+2] += 1            else:                return False        return True