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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def k_partitions(collection, k):
 """Generate all ``k``-partitions of a collection. Example: [[[0, 1], [2]], [[0], [1, 2]], [[0, 2], [1]]] """

    collection = list(collection)
    n = len(collection)

    # Special cases
    if n == 0 or k < 1:
        return []
    if k == 1:
        return [[collection]]

    a = [0] * (n + 1)
    for j in range(1, k + 1):
        a[n - k + j] = j - 1
    return _f(k, n, 0, n, a, k, collection)