Own Solution
I don't have much experience to use set and dictionary. So

class Solution:
    def findDifference(self, nums1: List[int], nums2: List[int]) -> List[List[int]]:
        nums1 = set(nums1) 
        nums2 = set(nums2)
        dict1,dict2 = {} ,{}
        result1,result2 = [],[]
        for i in nums1 :
            dict1.update({f'{i}':1})
        for i in nums2 :
            dict2.update({f'{i}':1})
        for number in nums1:
            if dict2.get(f'{number}') == None:
                result1.append(number)
        for number in nums2:
            if dict1.get(f'{number}') == None:
                result2.append(number)
        return result1, result2 

Chatgpt Solution:
directly use set operations to find the symmetric difference between the two sets created from the input lists.

class Solution:
    def findDifference(self, nums1: List[int], nums2: List[int]) -> List[List[int]]:
        set1 = set(nums1)
        set2 = set(nums2)
        
        result1 = list(set1 - set2)  # Elements in nums1 but not in nums2
        result2 = list(set2 - set1)  # Elements in nums2 but not in nums1
        
        return result1, result2