Finalize dandi example

[jbentvelsen]

See this comment #45 (comment) for a description of this issue.

[jbentvelsen]

May be a good idea to use only a subset of the dataset in the training example, as otherwise training may take very long.

[sdv96]

IS THIS ISSUE SOLVED I CAN IMPROVE IT By..... if @jbentvelse approves assign within 1 WEEKS {WORKING NOW}