What is the time complexity of this custom function?

Is it correct to say that the time complexity of the following code snippet is O(n^2)? My main doubt is whether I can consider triplets.append(sorted([array[i], array[j], twoSum - array[j]])) as constant time since it does not depend on N and is always sorting an array of fixed size of length 3.

Function

def threeNumberSum(array, targetSum): 
    triplets = []
    
    # O(n^2)
    for i in range(len(array)): 
        twoSum = targetSum - array[i]
        hashTable = {}
        for j in range(i+1, len(array)): 
            hashTable[array[j]] = twoSum - array[j] 
            y = hashTable.get(twoSum - array[j]) 
            if y != None and twoSum-array[j] != array[j]: 
                triplets.append(sorted([array[i], array[j], twoSum - array[j]])) # O(1)? 

    triplets.sort() # O(nlogn) 
    return triplets