[BUG] duplicate node IDs in Bitcoin Tutorial notebook cause unexpected rendering results

[DataBoyTX]

Noticed that some of the graphs in the BitcoinTutorial.ipynb are showing up black, tracked it down to dupe IDs from logic in the notebook, will apply a fix.

To Reproduce

1. Run notebook, see last viz

Expected behavior
colored nodes in the graph

[lmeyerov]

I think the validators can catch this, but probably a deeper backend issue we should explore for cases where validators aren't run, cc @aucahuasi