Convert strings of the form "(1, 2, 3), (4, 5, 6), (7, 8, 9)" into multidimensional arrays of the form [[1, 2, 3], [4, 5, 6], [7,8,9]].
"(1, 2, 3), (4, 5, 6), (7, 8, 9)"
[[1, 2, 3], [4, 5, 6], [7,8,9]]
