Write a function that takes in a non-empty array of distinct integers and an integer representing a target sum. The function should nd all quadruplets in the array that sum up to the target sum and return a two-dimensional array of all these quadruplets in no particular order. If no four numbers sum up to the target sum, the function should return an empty array.
Sample input: [7, 6, 4, -1, 1, 2], 16 Sample output: [[7, 6, 4, -1], [7, 6, 1, 2]]
Check this Python code.