In the Data directory, there is a subset of midi file (~3900) that we could start with. If you want, you can download the largest world MIDI corpus here:https://www.reddit.com/r/WeAreTheMusicMakers/comments/3ajwe4/the_largest_midi_collection_on_the_internet/
Package information for music21: http://web.mit.edu/music21/
In the Data folder, the ipython notebook provides some codes to extract note sequence from midi data and the json file is a sample of the extracted note sequences.
The code higher order network: https://github.com/xyjprc/hon