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def count_subset_pairs(collection):    total = sum(collection)    if total % 2 != 0:        return 0        n = len(collection)    mid = n // 2    left = collection[:mid]    right = collection[mid:]        from collections import defaultdict    left_counts = defaultdict(int)    for subset in generate_subsets(left):        left_counts[sum(subset)] += 1        right_counts = defaultdict(int)    for subset in generate_subsets(right):        right_counts[sum(subset)] += 1        target = total // 2    count = 0    for s in left_counts:        if (target - s) in right_counts:            count += left_counts[s] * right_counts[target - s]        return countdef generate_subsets(arr):    n = len(arr)    subsets = []    for i in range(1, 1 << n):        subset = []        for j in range(n):            if (i >> j) & 1:                subset.append(arr[j])        subsets.append(subset)    return subsets# ????test_collection = [1, 2, 3, 4, 5, 6]print(count_subset_pairs(test_collection))

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