Finds the best path (an array of x- and y-coordinates) to align `x`

to
`y`

, given the cost matrix `cost_mat = dtw_mat(x, y)`

.

- Parameters
**cost_mat**(N, M) np.ndarrayThe output of the `dtw_mat()`

function.

- Returns
**path**(L, 2) np.ndarrayThe path that aligns `x`

to `y`

in time.