Round-trip arr through the .npy binary format: serialize it, then deserialize it back into an array, and return the result. (In real code you'd save to and load from a filename; here use an io.BytesIO buffer instead, since this judge has no real filesystem to save to.)

Input

[[1 2 3]
 [4 5 6]]

Output

[[1 2 3]
 [4 5 6]]