Expand recursive list in Python

This will expand a list of lists into a single list of all the items in Python. [[1, 2, 3, 4, [4, 5, 3, 2]], 2, 3, 4, [5, 2, 4, 5]] becomes: [1, 2, 3, 4, 4, 5, 3, 2, 2, 3, 4, 5, 2, 4, 5]