mnist-example-runs-after-intro-evaluate.md

doctest
+FIXME

MNIST example runs after intro evaluate

After running evaluate on mnist-intro we get a second run.

>>> cd(example("models"))

>>> run("guild runs --limit 2")
[1:...]  mnist-intro:evaluate  ... ...  completed  train=...
[2:...]  mnist-intro:train     ... ...  completed  batch-size=100 epochs=1 lr=0.5
<exit 0>