def column_sums(square):
    """ Takes a magic square as parameter and returns
    a sum of each column in the square as an array. """
    res = []
    i = 0
    n = 0
    sum_sq = 0
    for (i, sq) in enumerate(square):
        j = 0
        sq_len = len(sq)
        while j < sq_len:
            if n >= len(square):
                print(sum_sq)
                res.append(sum_sq)
                sum_sq = 0
                n = 0
            sum_sq += square[j][i]
            j += 1
            n += 1
    return res

square = [
    [1, 2, 3, 4],
    [5, 6, 7, 8],
    [9, 10, 11, 12],
    [13, 14, 15, 16]
]
print(column_sums(square))