Convert multidimensional array to single dimensional

Hello Mate,
Let's discuss problem statement.
We have a multidimensional array and we have convert this array to single dimensional array with unique values very simple problem statement.
Example: [1,3,[5, 6, [7, [6, 5], 4], 3],[4]]
Output: [ 1, 3, 5, 6, 7, 4 ]