Change in order of assert after write causes move error

[Kingdutch]

It appears that the change in 5aaf53f now produces the following build error

error[E0382]: borrow of moved value: `dataset`
  --> src/koans/02_cluster_generation/06_dataset.rs:96:17
   |
80 |         let dataset = generate_dataset(n, centroids.view(), &mut rng);
   |             ------- move occurs because `dataset` has type `ndarray::ArrayBase<ndarray::OwnedRepr<f64>, ndarray::dimension::dim::Dim<[usize; 2]>>`, which does not implement the `Copy` trait
...
90 |         write_npy("python/dataset.npy", dataset).expect("Failed to write array in npy format.");
   |                                         ------- value moved here
...
96 |         assert!(dataset.genrows().into_iter().all(|r| r != array![0., 0.]));
   |                 ^^^^^^^ value borrowed here after move

error: aborting due to previous error

[LukeMathWalker]

Pushed a fix to master, thanks 👍