Degree Code Snippet doesn't consistently iterate over the nodes

[annaritz]

We currently cannot describe specific nodes in the tutorial (even with the Tutorial Network) because every time the graph is loaded, the iterators are not guaranteed to return the nodes/edges in the same order.

We may have to keep it like this - it's dangerous to impose an ordering when iterators by definition don't have an implicit ordering, since users may assume that's how python iterators work. That's why this is both a bug and a feature.

For now, we should write all tutorials without assuming a strict order for iteration.