chapter02_best_practices 07_unittests.ipynb nosetests fail

[pleabargain]

walked through the demo but got a fail mid way through

!nosetests

/bin/sh: 1: nosetests: not found

The notebook should have a sanity check to see if nose is installed at all... I've created a sample and attached same. updaedwithnoseinsallcheck07_unittests.ipynb.zip